add prune and remove unused packages

vendor/google.golang.org/appengine/internal/base/api_base.proto

@@ -1,33 +0,0 @@
-// Built-in base types for API calls. Primarily useful as return types.
-
-syntax = "proto2";
-option go_package = "base";
-
-package appengine.base;
-
-message StringProto {
-  required string value = 1;
-}
-
-message Integer32Proto {
-  required int32 value = 1;
-}
-
-message Integer64Proto {
-  required int64 value = 1;
-}
-
-message BoolProto {
-  required bool value = 1;
-}
-
-message DoubleProto {
-  required double value = 1;
-}
-
-message BytesProto {
-  required bytes value = 1 [ctype=CORD];
-}
-
-message VoidProto {
-}