lnrpc: update protoc invocation

This commit reflects an upstream change in grpc-gateway.

- regenerate proto output
- add genprotos dep, updated glide deps

lnrpc/gen_protos.sh

@@ -4,7 +4,7 @@
 protoc -I/usr/local/include -I. \
        -I$GOPATH/src \
        -I$GOPATH/src/github.com/grpc-ecosystem/grpc-gateway/third_party/googleapis \
-       --go_out=Mgoogle/api/annotations.proto=github.com/grpc-ecosystem/grpc-gateway/third_party/googleapis/google/api,plugins=grpc:. \
+       --go_out=plugins=grpc:. \
        rpc.proto