Make get_toolchain_if_necessary.py work on Mac again
Make get_toolchain_if_necessary.py work on Mac again

R=thakis@chromium.org, sebmarchand@chromium.org
BUG=495204,585829

Review URL: https://codereview.chromium.org/1689723002

git-svn-id: fd409f4bdeea2bb50a5d34bb4d4bfc2046a5a3dd@298720 0039d316-1c4b-4281-b951-d872f2087c98

primiano/depot_tools,CoherentLabs/depot_tools,CoherentLabs/depot_tools,primiano/depot_tools,primiano/depot_tools