[bugfix] Update create_package_installed.py

- Updates create_package_installed.py to match existing python scripts
Merge pull request #245 from redhatrises/python_match

[bugfix] Update create_package_installed.py
Updated RHEL7 XCCDF to reflect OS is RHEL 7
[rhel7] removing auxiliary/transition_notes.xml

This was made during RHEL6 STIG process. It may prove useful for RHEL7, but
dropping for now
Updated RHEL7 content to reflect RHEL 7

- Updated intro text
- Updated XSLT transforms to use RHEL7 in titles