Issue #4 - Exit with error on apply error, but catch in cascade apply.

If a patch fails to apply we should exit with a proper exit status so that ansible can catch the issue in non-interactive operation for the sandboxes.

Test plan You can use echo $? after executing any command in the shell to see the last commands exit code.. 0 for success, 1 for failure.

To test this patch try doing a git bz apply using a bug you know will fail to apply, Call the echo statement above and note the exit code is 0.. after applying the patch do the same bz apply and echo and not the exit code now properly reflects the failure state with an exit code of 1.

Bonus points is to test that the cascade apply still works as expected for both cases of a fully successful apply and for one where one of the dependancies fails to apply.

More bonus points, check that passing multiple bug ids also still works