database/sql: remove forced log import from test

This var _ = log.Printf line was added 8 years ago, in CL 4973055,
which created the database/sql package and its tests. There was no
goimports back then, so this was likely added to make it easier to
use log package during development of tests.

It's no longer needed, so remove it. It can always be conveniently
re-added via goimports whenever needed.

Change-Id: I7c32ae3e593c194d970920084139dfa5a42386dc
Reviewed-on: https://go-review.googlesource.com/c/go/+/202481
Run-TryBot: Dmitri Shuralyov <dmitshur@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

src/database/sql/fakedb_test.go

@@ -10,7 +10,6 @@ import (
 	"errors"
 	"fmt"
 	"io"
-	"log"
 	"reflect"
 	"sort"
 	"strconv"
@@ -20,8 +19,6 @@ import (
 	"time"
 )
 
-var _ = log.Printf
-
 // fakeDriver is a fake database that implements Go's driver.Driver
 // interface, just for testing.
 //