Explicitly rename git2go import.

Change-Id: I526946a4e3a800d6d5b94fb7528ad71af8b9e06a

cmd/slothfs-deref-manifest/main.go

diff --git a/cmd/slothfs-deref-manifest/main.go b/cmd/slothfs-deref-manifest/main.go
index dd50a66..ee2432d 100644
--- a/cmd/slothfs-deref-manifest/main.go
+++ b/cmd/slothfs-deref-manifest/main.go
@@ -24,7 +24,7 @@
 	"path/filepath"
 
 	"github.com/google/slothfs/manifest"
-	"github.com/libgit2/git2go"
+	git "github.com/libgit2/git2go"
 )
 
 func main() {