Add code for multi host executions.
restraint_multi_free iterates through EXISTING_NODES variable and
updates the restraint xml to replace hostname value with the actuals.
It also constructs restraint command as per the number of nodes available.

Signed-off-by: Gowrishankar Rajaiyan <gsr@redhat.com>
Merge branch 'dev' of github.com:gsr-shanks/nexus into dev

Signed-off-by: Gowrishankar Rajaiyan <gsr@redhat.com>

Conflicts:
	etc/ipa.conf