Add a finite timeout value to be used in GCE and MVM python agents.
Add a finite timeout value to be used in GCE and MVM python agents.

This is similar to CL/134140973. I observed that when a MVM instance is
created, the very first API calls have trouble making HTTP calls, and these
calls get stuck indefinitely due to infinite timeout.

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Created by MOE: https://github.com/google/moe
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GoogleCloudPlatform/cloud-debug-python,GoogleCloudPlatform/cloud-debug-python,GoogleCloudPlatform/cloud-debug-python