GCE GAPIC is not applying timeout or retry from config file

[vchudnov-g]

The compute_grpc_service_config.json defines a timeout and a retryPolicy that are NOT being applied in the generated GAPIC's transports/base.py.

By way of comparison, vision_grpc_service_config.json defines the same timeout and a retryPolicy that ARE being applied in the generated GAPIC's transports/base.py.

This suggests the generator or higher level pipelines are not reading the these policies. It's possibly a REGAPIC- or DIREGAPIC-specific issue.

Tangentially related: #1897