Fetch information in bulk about projects.

Reduce the number of datastore api calls at startup when the meta data
about all projects is gathered. Three calls are reduced to one for
each project.

Change-Id: Ia257515e5c4e7d62c662c49f24ba68055c4e55fd
Provide a specific error message when rpc is incompatible

Change-Id: Id9f5ae4ef8f1d2fe0b69f3051cfa418f778abf7e