mysql: runtime error: slice bounds out of range in packets.go

Issue description

When using many concurrent SQL queries (same pool), I get a slice out of bounds error. The corresponding logic in jmoiron/sqlx seems fine. It’s just a call to (*Rows).Next() which is causing this.

Similar to #36 perhaps?

Error log

panic: runtime error: slice bounds out of range

goroutine 4814 [running]:
mypackage/vendor/github.com/go-sql-driver/mysql.(*binaryRows).readRow(0xc4205a2160, 0xc422be3140, 0xc, 0xc, 0xc, 0xc422be3080)
	/home/gm42/projects/mypackage/src/mypackage/vendor/github.com/go-sql-driver/mysql/packets.go:1168 +0x92d
mypackage/vendor/github.com/go-sql-driver/mysql.(*binaryRows).Next(0xc4205a2160, 0xc422be3140, 0xc, 0xc, 0xc, 0xc)
	/home/gm42/projects/mypackage/src/mypackage/vendor/github.com/go-sql-driver/mysql/rows.go:85 +0x5e
database/sql.(*Rows).nextLocked(0xc422b6da80, 0xc4206ac4b0)
	/usr/local/go/src/database/sql/sql.go:2149 +0x6c
database/sql.(*Rows).Next.func1()
	/usr/local/go/src/database/sql/sql.go:2134 +0x3c
database/sql.withLock(0xeb1640, 0xc422b6dab0, 0xc4206ac4f0)
	/usr/local/go/src/database/sql/sql.go:2545 +0x65
database/sql.(*Rows).Next(0xc422b6da80, 0xb82ce0)
	/usr/local/go/src/database/sql/sql.go:2135 +0x83
mypackage/vendor/github.com/jmoiron/sqlx.(*Row).Scan(0xc4223b0870, 0xc422be2fc0, 0xc, 0xc, 0x0, 0x0)

Configuration

Driver version (or git SHA): 1421caf44f6464fd2ee8de694c7508ee13f92964

Go version: go version go1.8.1 linux/amd64

Server version: MySQL 5.6.27

Server OS: Ubuntu 16