Fix a crash when Paramiko has trouble with loading a host key.
Review Request #11110 — Created Aug. 2, 2020 and submitted
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
We now check for this and just skip the key.
Encountered this locally and saw it affect unit test runs and some
repository interaction. After the patch, everything worked as expected.