k8s: Reset() the rest mapper if it fails to map an existing type. Fixes https://github.com/windmilleng/tilt/issues/3325

[nicks]

Hello @maiamcc,

Please review the following commits I made in branch nicks/ch6999:

1d6f85d (2020-05-14 10:52:37 -0400)
k8s: Reset() the rest mapper if it fails to map an existing type. Fixes #3325

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[maiamcc]

ooh nice, this fix is way simpler than I anticipated! Did you test it with the repro case in #3325 or should I?

[nicks]

Yes! I tested it with tilt ci. I actually created a small integration test framework with tilt ci just to test this, but this specific example was slower than I wanted (i.e., it takes about 90 seconds to run) so i kicked it out of the PR