rpc in REST Streaming Fragment test is missing the http annotation

[parthea]

There is a fragment test for testing REST streaming however the REST code would not be exercised because the http annotation is missing in the rpc.

gapic-generator-python/tests/fragments/test_rest_streaming.proto

Lines 24 to 27 in 90ba3f7

	rpc MyMethod(MethodRequest) returns (stream MethodResponse) {
	option (google.api.method_signature) = "from,class,import,any,license,type";
	}
	}