User sync drops permissions if GH request failed

[sarahhodne]

Occasionally the GH requests fail in gatekeeper. Since all permissions are dropped before this, this means that all repositories will "disappear" for a user until the next sync 24 hours later.

We should probably add a retry of some sort, or wait with dropping the permission until the request succeeded.

(By "failing" requests here I mean in the "could not connect to server" sense. I also saw a null pointer exception in the logs related to the request.)

[BanzaiMan]

The latter approach seems reasonable.