Convert everything to use vendor/

hack/verify-codecgen.sh

@@ -31,7 +31,7 @@ generated_files=($(
         -o -wholename './release' \
         -o -wholename './target' \
         -o -wholename '*/third_party/*' \
-        -o -wholename '*/Godeps/*' \
+        -o -wholename '*/vendor/*' \
       \) -prune \
     \) -name '*.generated.go'))