Fix a crash when Paramiko has trouble with loading a host key.
Review Request #1995 — Created Sept. 7, 2020 and updated
It's possible for Paramiko to raise an exception if it can't load a host key that's in a format it doesn't understand. This breaks any attempts at loading host keys. This is most likely to happen on a developer setup. We now check for this and just skip the key. Testing Done: Encountered this locally and saw it affect unit test runs and some repository interaction. After the patch, everything worked as expected. Reviewed at https://reviews.reviewboard.org/r/11110/