Merge github.com:grpc/grpc into cpp_bazelness

src/php/ext/grpc/call.c

src/php/ext/grpc/call_credentials.c

src/php/ext/grpc/channel.c

src/php/ext/grpc/channel_credentials.c

src/php/ext/grpc/server.c

src/php/ext/grpc/server_credentials.c

src/php/ext/grpc/timeval.c