scripts: make glide-update clean up unnecessary files for etcd,grpc

As fleet needs only some parts of etcd, grpc, and gogo/protobuf,
glide-update.sh should clean up unnecessary directories to keep vendor
trees as small as possible.

Also remove --keep from glide-vc, as internal packages are already
correctly handled by glide.

scripts/glide-update.sh

@@ -21,6 +21,29 @@ fi
 
 glide update --strip-vcs --strip-vendor --update-vendored --delete
 glide vc --only-code --no-tests --no-legal-files
-# NOTE: we cannot remove vendor/golang.org/x/net/internal to avoid build errors
-#       that internal packages cannot be imported.
-git checkout vendor/golang.org/x/net/internal
+
+# manual cleanup to reduce size of vendor trees
+
+ETCD_CLEANUP_DIRS="\
+ alarm auth clientv3 cmd compactor contrib discovery e2e embed etcdctl \
+ etcdmain etcdserver hack integration lease logos mvcc proxy raft rafthttp \
+ scripts snap store tools version wal \
+"
+
+pushd vendor/github.com/coreos/etcd
+	rm -rf $ETCD_CLEANUP_DIRS
+popd
+
+GRPC_CLEANUP_DIRS="benchmark examples test"
+
+pushd vendor/google.golang.org/grpc
+	rm -rf $GRPC_CLEANUP_DIRS
+popd
+
+GOGOPROTOBUF_CLEANUP_DIRS="test vanity/test"
+
+pushd vendor/github.com/gogo/protobuf
+	rm -rf $GOGOPROTOBUF_CLEANUP_DIRS
+popd
+
+rm -rf vendor/github.com/godbus/dbus/_examples