Minor fixups for the stacktira bootstrap script

- ruby-augeas requires gcc since it's a native extension.
It was also previously bundled in with the puppet install, which made
its state invisible to the installer. Before installing puppet,
this patch installs gcc if needed, installs the gem, then removes gcc

- epel was being handled in a very blunt manner for libyaml install.
This patch makes a quick search to see if epel is already enabled on
the node, and installs it only if it isn't there.

Change-Id: Ib67fdd86089855cead228725d7cbc2e61634ff53
Drop obsolete Galera references

Once we decide to use Michael's puppet-galera
module, we'll need to drop these obsolete
references to old galera module.

Change-Id: I2cd47193caec2fda3fb3e2cf332c977f4a8e5e78
Data mappings for Galera in full_ha deployments

More data mapping cleanups for using Michael Chapman's puppet-galera
module with full_ha deployments.

Change-Id: If383652c8bf9b26af093ff2ecd4b207cf197fdb3
BP: switch-to-percona
Merge "Drop obsolete Galera references"
Merge "Minor fixups for the stacktira bootstrap script"
Merge remote-tracking branch 'upstream/master' into icehouse