godep restore should retry on transient failures

[rmmh]

godep restore should retry on transient errors from the underlying VCS (5xx, connection error). This would make automated godep restores more reliable.

Others have found retrying git commands worthwhile: git-retry exists (used by Chrome's build system), and the just-released Git 2.10 retries once on submodule clone failures:

submodule update and clone --recursive have learned to retry a single cloning failure for each submodule, to make ephemeral server and network failures less annoying.

[freeformz]

I am closing this issue because the repo is going to be archived.