Related to #138

Convert module to string before appending it to the base path to search for
existing modules...

When running on CentOS or RHEL the opcache package under php 5.4
us named php-pecl-zendopcache.
When using a newer PHP version like 5.6, 7.0 or 7.1 the package
is named slightly different though: php-opcache.

Take this into account.

As RHEL and CentOS are both longer-lived enterprise-class operating
systems the software versions are usually lagging a bit behind.

In case one wants the longevity of an Enterprise Linux together with
more modern software the Softwarecollections project exists which
offers amongst others more modern PHP releases.

This commit adds a pillar toggle to use the SCL repo and the ability
to select which php version to install.

This will make state names play nicely with gentoo.

(Command was not working on Ubuntu 16.04.)
Both Ubuntu's and RedHat's man pages of test list -gt, but not >
as their 'greater than' operator.

added

  - php.ng.filter
  - php.ng.hash
  - php.ng.openssl
  - php.ng.phar