<install> refactor rhsm+rhn conf; preflight checks

rhsm repo conf options outsourced to a function so maintenance requires
only changing the repo name in one place.
Same thing for "rhn" method; also made this idempotent so can rerun the
install without filling up the plugin conf.
Preflight checks now look for user/pass on rhn/rhsm (now consolidated
into common var names).
Also removed a minor preflight problem where rpm -V fails for no good
reason on a re-install; used plain rpm -q instead to test rpmdb.

Conflicts:
	enterprise/install-scripts/amazon/openshift-amz.sh
	enterprise/install-scripts/generic/openshift.sh
	enterprise/install-scripts/openshift.ks
<install> use infra or node to get priorities plugin

Conflicts:
	enterprise/install-scripts/amazon/openshift-amz.sh
	enterprise/install-scripts/generic/openshift.sh
	enterprise/install-scripts/openshift.ks
<install> provide options for several DNS situations
<install> extend no_jboss* vars to v1 carts
<install> work around ycm bug for RHSM
<install> subscribe multiple RHSM poolids
Merge pull request #119 from sosiouxme/enterprise-1.2

Enterprise 1.2