Dep upgrade mysql lib (#4161)

*  update gopkg file to add sql dep

vendor/github.com/go-sql-driver/mysql/driver.go

@@ -4,7 +4,7 @@
 // License, v. 2.0. If a copy of the MPL was not distributed with this file,
 // You can obtain one at http://mozilla.org/MPL/2.0/.
 
-// Package mysql provides a MySQL driver for Go's database/sql package
+// Package mysql provides a MySQL driver for Go's database/sql package.
 //
 // The driver should be used via the database/sql package:
 //
@@ -20,8 +20,14 @@ import (
 	"database/sql"
 	"database/sql/driver"
 	"net"
+	"sync"
 )
 
+// watcher interface is used for context support (From Go 1.8)
+type watcher interface {
+	startWatcher()
+}
+
 // MySQLDriver is exported to make the driver directly accessible.
 // In general the driver is used via the database/sql package.
 type MySQLDriver struct{}
@@ -30,12 +36,17 @@ type MySQLDriver struct{}
 // Custom dial functions must be registered with RegisterDial
 type DialFunc func(addr string) (net.Conn, error)
 
-var dials map[string]DialFunc
+var (
+	dialsLock sync.RWMutex
+	dials     map[string]DialFunc
+)
 
 // RegisterDial registers a custom dial function. It can then be used by the
 // network address mynet(addr), where mynet is the registered new network.
 // addr is passed as a parameter to the dial function.
 func RegisterDial(net string, dial DialFunc) {
+	dialsLock.Lock()
+	defer dialsLock.Unlock()
 	if dials == nil {
 		dials = make(map[string]DialFunc)
 	}
@@ -52,16 +63,19 @@ func (d MySQLDriver) Open(dsn string) (driver.Conn, error) {
 	mc := &mysqlConn{
 		maxAllowedPacket: maxPacketSize,
 		maxWriteSize:     maxPacketSize - 1,
+		closech:          make(chan struct{}),
 	}
 	mc.cfg, err = ParseDSN(dsn)
 	if err != nil {
 		return nil, err
 	}
 	mc.parseTime = mc.cfg.ParseTime
-	mc.strict = mc.cfg.Strict
 
 	// Connect to Server
-	if dial, ok := dials[mc.cfg.Net]; ok {
+	dialsLock.RLock()
+	dial, ok := dials[mc.cfg.Net]
+	dialsLock.RUnlock()
+	if ok {
 		mc.netConn, err = dial(mc.cfg.Addr)
 	} else {
 		nd := net.Dialer{Timeout: mc.cfg.Timeout}
@@ -81,6 +95,11 @@ func (d MySQLDriver) Open(dsn string) (driver.Conn, error) {
 		}
 	}
 
+	// Call startWatcher for context support (From Go 1.8)
+	if s, ok := interface{}(mc).(watcher); ok {
+		s.startWatcher()
+	}
+
 	mc.buf = newBuffer(mc.netConn)
 
 	// Set I/O timeouts
@@ -88,20 +107,31 @@ func (d MySQLDriver) Open(dsn string) (driver.Conn, error) {
 	mc.writeTimeout = mc.cfg.WriteTimeout
 
 	// Reading Handshake Initialization Packet
-	cipher, err := mc.readInitPacket()
+	authData, plugin, err := mc.readHandshakePacket()
 	if err != nil {
 		mc.cleanup()
 		return nil, err
 	}
 
 	// Send Client Authentication Packet
-	if err = mc.writeAuthPacket(cipher); err != nil {
+	authResp, addNUL, err := mc.auth(authData, plugin)
+	if err != nil {
+		// try the default auth plugin, if using the requested plugin failed
+		errLog.Print("could not use requested auth plugin '"+plugin+"': ", err.Error())
+		plugin = defaultAuthPlugin
+		authResp, addNUL, err = mc.auth(authData, plugin)
+		if err != nil {
+			mc.cleanup()
+			return nil, err
+		}
+	}
+	if err = mc.writeHandshakeResponsePacket(authResp, addNUL, plugin); err != nil {
 		mc.cleanup()
 		return nil, err
 	}
 
 	// Handle response to auth packet, switch methods if possible
-	if err = handleAuthResult(mc); err != nil {
+	if err = mc.handleAuthResult(authData, plugin); err != nil {
 		// Authentication failed and MySQL has already closed the connection
 		// (https://dev.mysql.com/doc/internals/en/authentication-fails.html).
 		// Do not send COM_QUIT, just cleanup and return the error.
@@ -134,43 +164,6 @@ func (d MySQLDriver) Open(dsn string) (driver.Conn, error) {
 	return mc, nil
 }
 
-func handleAuthResult(mc *mysqlConn) error {
-	// Read Result Packet
-	cipher, err := mc.readResultOK()
-	if err == nil {
-		return nil // auth successful
-	}
-
-	if mc.cfg == nil {
-		return err // auth failed and retry not possible
-	}
-
-	// Retry auth if configured to do so.
-	if mc.cfg.AllowOldPasswords && err == ErrOldPassword {
-		// Retry with old authentication method. Note: there are edge cases
-		// where this should work but doesn't; this is currently "wontfix":
-		// https://github.com/go-sql-driver/mysql/issues/184
-		if err = mc.writeOldAuthPacket(cipher); err != nil {
-			return err
-		}
-		_, err = mc.readResultOK()
-	} else if mc.cfg.AllowCleartextPasswords && err == ErrCleartextPassword {
-		// Retry with clear text password for
-		// http://dev.mysql.com/doc/refman/5.7/en/cleartext-authentication-plugin.html
-		// http://dev.mysql.com/doc/refman/5.7/en/pam-authentication-plugin.html
-		if err = mc.writeClearAuthPacket(); err != nil {
-			return err
-		}
-		_, err = mc.readResultOK()
-	} else if mc.cfg.AllowNativePasswords && err == ErrNativePassword {
-		if err = mc.writeNativeAuthPacket(cipher); err != nil {
-			return err
-		}
-		_, err = mc.readResultOK()
-	}
-	return err
-}
-
 func init() {
 	sql.Register("mysql", &MySQLDriver{})
 }