[COOK-2434] Better support for SUSE distribution

https://tickets.opscode.com/browse/COOK-2434

* recipes/default.rb:
  - Corrected service commands
  - Corrected support for `a2enmod` and `a2dismod`
  - Corrected support for template in `/etc/sysconfig`. Now path is
    parameterized with the name of the package.
  - Corrected path to `httpd.conf`
* templates/default/apache2.conf.erb:
  - Specified platform family
* templates/default/etc-sysconfig-httpd.erb:
  - Typo
* templates/suse/etc-sysconfig-httpd.erb:
  - Created specific template for `/etc/sysconfig/apache2`
* attributes/default.rb:
  - SUSE-specific attribute values. Added `['apache']['docroot']`
  attribute to the default ones. I think it could be useful to determine the
  node-level prefix of the vhosts.