Use -q flag instead of array slices

Previously we sliced off the informational output lines. This
broke on rabbitmq 3.4.0 because the 'done' was removed. We can use
the -q flag to never print them in the first place.
Update unit tests to handle new -q flag

Updated the rabbitmq_user, rabbitmq_user_permissions, and
rabbitmq_vhost spec tests to correctly mock the rabbitmqctl command
with the -q flag. Also added one missed -q to a list users call.
Merge pull request #1 from cmurphy/fix_fix_340

Update unit tests to handle new -q flag
Merge pull request #251 from nibalizer/fix_340

Use -q flag instead of array slices