Reached maximum allowed user repos error on Cloud

Created by: benjaminwgordon

• Sourcegraph version: Sourcegraph.com

Steps to reproduce:

1. Attempt to sync additional repositories through the "Your Repositories" menu
2. Wait for the sync
3. Reload the "Your Repositories" page

Expected behavior:

New added repositories should be synced as expected

Actual behavior:

After the sync fails, the GitHub code host is marked as unreachable: