Clean up gtest_prod mess.

Change-Id: I7b9b800c65cfc918770cd54b77993d2f0f2c0df6
diff --git a/aos/common/BUILD b/aos/common/BUILD
index 55f1a03..919c2a0 100644
--- a/aos/common/BUILD
+++ b/aos/common/BUILD
@@ -117,15 +117,12 @@
 
 cc_library(
   name = 'gtest_prod',
-  deps = [
-    '//third_party/gtest_prod',
-  ],
 )
 
 cc_library(
   name = 'once',
   deps = [
-    '//third_party/gtest_prod',
+    ':gtest_prod',
   ],
 )