Added passenger_pkgs_state var and some fixes.

defaults/main.yml:
- passenger_pkgs_state now allows you to define if you want to install
  or update the packages, to avoid unexpected updates and changes on
  your hosts.

tasks/pkgs.yml:
- Added 'cache_valid_time' with a 3600 seconds (1 hour) value.

tests/apache/Vagrantfile:
- Added a shell provision for installing python-pycurl before running
  ansible.