Added 'Exec' resource for path value in config.pp and install.pp. Removed invalid parameter 'template' from config.pp.

This may be unnecessary, if a person forking this repo has a global path set in "site.pp" or elsewhere. When I installed this via "puppet module," created a manifest to "include the modules" then hit that manifest with "puppet apply,"  I got errors like "'pip install carbon' is not qualified and no path was specified. Please qualify the command or specify a path" when I attempted to run this out of the box. Also, noticed that the "template" attribute in the apache::vhost definition does not seem to actually exist when I perused the apache module directory, so removed that line totally. Cannot speak to whether or not there is an attribute that this line should be amended to.