[mediacapture-main] Travis is failing git checkout with "reference is not a tree" (#581)

henbos has just created a new issue for https://github.com/w3c/mediacapture-main:

== Travis is failing git checkout with "reference is not a tree" ==
We tried with three different PRs and get (#576, #579 and #580 ):

Unhandled rejection Error: Command failed: /usr/bin/git checkout 7b144b3b83ce296d5b29c5e4fc2ea2a65e9d3f32
fatal: reference is not a tree: 7b144b3b83ce296d5b29c5e4fc2ea2a65e9d3f32

The last one was uploaded from a different checkout of a different fork on a different machine.

@dontcallmedom are you the right person to take a look at Travis failures?

Please view or discuss this issue at https://github.com/w3c/mediacapture-main/issues/581 using your GitHub account