database/sql: Alter *DB.begin to return driver.ErrBadConn when driver.Conn.Begin...

Fixes #4433

R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/6845094

diff --git a/src/pkg/database/sql/sql.go b/src/pkg/database/sql/sql.go
index b0cba949c6bd9e70f7715bd01b150e209b5ddcd6..e59d0130d5ea75ab99d68ae13027ee9cb77ca51f 100644 (file)
--- a/src/pkg/database/sql/sql.go
+++ b/src/pkg/database/sql/sql.go
@@ -426,7 +426,7 @@ func (db *DB) begin() (tx *Tx, err error) {
        txi, err := ci.Begin()
        if err != nil {
                db.putConn(ci, err)
-               return nil, fmt.Errorf("sql: failed to Begin transaction: %v", err)
+               return nil, err
        }
        return &Tx{
                db:  db,