Update import paths for changes to blueprint

Blueprint has been modified to include a canonical import path,
update soong to match.

Change-Id: If29d31afbf3bf2e6364961a66456fa5f8f738455
diff --git a/glob/glob.go b/glob/glob.go
index 45ba285..eb4d1ab 100644
--- a/glob/glob.go
+++ b/glob/glob.go
@@ -20,7 +20,7 @@
 	"path/filepath"
 	"strings"
 
-	"blueprint/deptools"
+	"github.com/google/blueprint/deptools"
 )
 
 func IsGlob(glob string) bool {