Fix go vet errors

Docker-DCO-1.1-Signed-off-by: Alexandr Morozov <lk4d4math@gmail.com> (github: LK4D4)

Docker-DCO-1.1-Signed-off-by: Victor Vieux <vieux@docker.com> (github: vieux)

pkg/graphdb/graphdb_test.go

@@ -1,13 +1,14 @@
 package graphdb
 
 import (
-	_ "code.google.com/p/gosqlite/sqlite3"
 	"database/sql"
 	"fmt"
 	"os"
 	"path"
 	"strconv"
 	"testing"
+
+	_ "code.google.com/p/gosqlite/sqlite3"
 )
 
 func newTestDb(t *testing.T) (*Database, string) {
@@ -535,6 +536,6 @@ func TestConcurrentWrites(t *testing.T) {
 		}
 	}
 	if any {
-		t.Fatal()
+		t.Fail()
 	}
 }