Fix docstring which breaks doc generation

Generating the documentation fails because the inherited docstring for
HTTPAdapter.send() gives a warning and warnings are treated as errors.
This patch fixes this by putting a sane docstring for the overridden
method.

Change-Id: Ief6c7964848e4acec29457bc29c327ce161524f7

oslo_vmware/service.py

@@ -152,6 +152,7 @@ class LocalFileAdapter(requests.adapters.HTTPAdapter):
 
     def send(self, request, stream=False, timeout=None,
              verify=True, cert=None, proxies=None):
+        """Sends request for a local file."""
         return self._build_response_from_file(request)