Duplicate import statement for google.longrunning.operations_pb2 in python-logging

[parthea]

In PR googleapis/python-logging#746, there is a duplicate import statement for google.longrunning.operations_pb2. See the review comment here.

[parthea]

I was able to re-create the issue in 5e03e71 using the latest version of googleapis/googleapis . #1726 fixes the problem. I had to back out the update of googleapis/googleapis in #1726 because it caused a large change to the golden files. The update of googleapis/googleapis should be done in a separate PR.

[parthea]

I had to back out the addition of service YAML files in #1726 because it caused a large change to the golden files. The addition of service YAMLs should be done in a separate PR.