Make Varnish 4 a first-class template, add storage_type.

This will allow Varnish 3 or 4 to run in malloc mode.
Add validation for ::varnish::storage_type.
Malloc derp.
Fix validation if params are actually integers.
Make thread settings actually work on Varnish 4.
Allow changing vcl_reload.

This is important since Varnish 4 puts it in /usr/sbin instead of
/usr/bin.
Add el7 yum repository
Merge branch 'master' of github.com:phase2/puppet-varnish
Fix ending quote
Separate daemon environment files for el6 and el7
Systemd not support interpolation in environmentfile
Merge pull request #3 from thanandorn/master

Add support for Varnish 4 on el7