Install python27 SCL packages

Card online_runtime_156 - Python 2.7 from SCL [cart]
https://trello.com/c/IUo215zy
Remove python 2.7-community

Directory changes:
versions/shared/bin => versions/3.3/bin
versions/2.7        => REMOVED

Card online_runtime_156 - Python 2.7 from SCL [cart]
https://trello.com/c/IUo215zy
Enable python27 SCL functionality

Directory changes:
versions/2.7    => REMOVED
versions/3.3    => versions/3.3-community
versions/native => versions/{2.6,2.7,2.7-scl}

Add python_context script for both RHEL and Fedora.

Card online_runtime_156 - Python 2.7 from SCL [cart]
https://trello.com/c/IUo215zy
Make python update-configuration compatible with scl

Remove wait_for_stop from lib/util, as it's already provided by the cartridge sdk.

Card online_runtime_156 - Python 2.7 from SCL [cart]
https://trello.com/c/IUo215zy