downgrade mysql driver version (pingcap#1193)

* downgrade mysql driver version

* use v1.4.1

* use v1.3.0

go.mod

@@ -7,7 +7,7 @@ require (
 	github.com/cznic/sortutil v0.0.0-20181122101858-f5f958428db8
 	github.com/cznic/strutil v0.0.0-20171016134553-529a34b1c186
 	github.com/cznic/y v0.0.0-20170802143616-045f81c6662a
-	github.com/go-sql-driver/mysql v1.5.0
+	github.com/go-sql-driver/mysql v1.3.0
 	github.com/pingcap/check v0.0.0-20190102082844-67f458068fc8
 	github.com/pingcap/errors v0.11.5-0.20201029093017-5a7df2af2ac7
 	github.com/pingcap/log v0.0.0-20200511115504-543df19646ad

go.sum

@@ -15,8 +15,8 @@ github.com/cznic/y v0.0.0-20170802143616-045f81c6662a/go.mod h1:1rk5VM7oSnA4vjp+
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
-github.com/go-sql-driver/mysql v1.5.0 h1:ozyZYNQW3x3HtqT1jira07DN2PArx2v7/mN66gGcHOs=
-github.com/go-sql-driver/mysql v1.5.0/go.mod h1:DCzpHaOWr8IXmIStZouvnhqoel9Qv2LBy8hT2VhHyBg=
+github.com/go-sql-driver/mysql v1.3.0 h1:pgwjLi/dvffoP9aabwkT3AKpXQM93QARkjFhDDqC1UE=
+github.com/go-sql-driver/mysql v1.3.0/go.mod h1:zAC/RDZ24gD3HViQzih4MyKcchzm+sOG5ZlKdlhCg5w=
 github.com/google/renameio v0.1.0/go.mod h1:KWCgfxg9yswjAJkECMjeO8J8rahYeXnNhOm40UhjYkI=
 github.com/kisielk/gotool v1.0.0/go.mod h1:XhKaO+MFFWcvkIS/tQcRk01m1F5IRFswLeQ+oQHNcck=
 github.com/kr/pretty v0.1.0 h1:L/CwN0zerZDmRFUapSPitk6f+Q3+0za1rQkzVuMiMFI=
@@ -31,7 +31,6 @@ github.com/pingcap/errors v0.11.5-0.20201029093017-5a7df2af2ac7 h1:wQKuKP2HUtej2
 github.com/pingcap/errors v0.11.5-0.20201029093017-5a7df2af2ac7/go.mod h1:G7x87le1poQzLB/TqvTJI2ILrSgobnq4Ut7luOwvfvI=
 github.com/pingcap/log v0.0.0-20200511115504-543df19646ad h1:SveG82rmu/GFxYanffxsSF503SiQV+2JLnWEiGiF+Tc=
 github.com/pingcap/log v0.0.0-20200511115504-543df19646ad/go.mod h1:4rbK1p9ILyIfb6hU7OG2CiWSqMXnp3JMbiaVJ6mvoY8=
-github.com/pkg/errors v0.8.1 h1:iURUrRGxPUNPdy5/HRSm+Yj6okJ6UtLINN0Q9M4+h3I=
 github.com/pkg/errors v0.8.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
 github.com/pkg/errors v0.9.1 h1:FEBLx1zS214owpjy7qsBeixbURkuhQAwrK5UwLGTwt4=
 github.com/pkg/errors v0.9.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
@@ -45,7 +44,6 @@ github.com/stretchr/testify v1.3.0/go.mod h1:M5WIy9Dh21IEIfnGCwXGc5bZfKNJtfHm1UV
 github.com/stretchr/testify v1.4.0 h1:2E4SXV/wtOkTonXsotYi4li6zVWxYlZuYNCXe9XRJyk=
 github.com/stretchr/testify v1.4.0/go.mod h1:j7eGeouHqKxXV5pUuKE4zz7dFj8WfuZ+81PSLYec5m4=
 go.uber.org/atomic v1.3.2/go.mod h1:gD2HeocX3+yG+ygLZcrzQJaqmWj9AIm7n08wl/qW/PE=
-go.uber.org/atomic v1.6.0 h1:Ezj3JGmsOnG1MoRWQkPBsKLe9DwWD9QeXzTRzzldNVk=
 go.uber.org/atomic v1.6.0/go.mod h1:sABNBOSYdrvTF6hTgEIbc7YasKWGhgEQZyfxyTvoXHQ=
 go.uber.org/atomic v1.7.0 h1:ADUqmZGgLDDfbSL9ZmPxKTybcoEYHgpYfELNoN+7hsw=
 go.uber.org/atomic v1.7.0/go.mod h1:fEN4uk6kAWBTFdckzkM89CLk9XfWZrxpCo0nPH17wJc=