Worked on Fedora 20 examples in HOT

Fixed the image names in hot/F20/WordPress_Native.yaml to match what
DevStack will do with date-independent configuration.  Adapted the
2-instance WordPress example.
Turned off SELinux where it hurts.

Change-Id: I373700de873e6e375622ab65bd4a175af96d217f
Partial-Bug: #1305425
Merge "Worked on Fedora 20 examples in HOT"