I think calling os.Exit at arbitrary points is _bad_ and is good to
delete. I think panics in the case of data courruption have a chance
of providing useful information.
We moved some files further down in the directory structure in #6964, which
caused the relative paths to the mockery wrapper to stop working.
There does not seem to be an obvious way to get the module root as a default
environment variable, so for now I just added the extra up-slashes.
