Make the test script clean up all pyc files even if there are some in cwd

The *.pyc was unquoted and hence (if there were pyc file in the
current directory) expanded by the shell. By quoting it, we make sure
the glob does not get evaluated by the shell, but gets passed to find

Change-Id: I4d1f2383cdd84f42adf28569b27df5957c9f6010