OS X doesn't call md5sum by its full name. Instead, it is installed as simple 'md5'. Because we don't know what OS we're deploying to ahead of time, we need to check that condition for that in the shim script and account for it.
Using the same technique as the python path checker to determine the correct md5 command. This improves the previous technique.
Merge pull request #8080 from cachedout/osx_ssh_shim_md5

OS X doesn't call md5sum by its full name. Instead, it is installed as s...