apache2_module: whitespace cleanup

Remove trailing whitespace.
apache2_module: Handle dep resolution

The apache2_module module did not properly handle when a2enmod would
handle apache module dependancies.  It would always return a state of
changed.  I've updated the regular expression to properly parse that
output as well as the normal output.  A good example of this is the
mod_proxy_http module.
Merge pull request #7520 from jjneely/a2enmod

apache2_module module fixes