install pacemaker-mgmt package for hb_gui to work

It turns out pacemaker-mgmt must be installed *before* the openais
service starts.
add a hint about changing the hb_gui field to true
Merge pull request #35 from vuntz/no-underscore-hostname

Translate _ from pacemaker proposal name to - in hostnames
rename #expect_definitions to #stub_shellout and document

This method was previously misnamed - we are not setting any
expectations, but instead stubbing Mixlib::ShellOut so that
its #stdout command returns given values which can then be
tested against.

Also rename the parameters for clarity, and add some explanatory
comments.
add support for testing scenarios where commands fail
handle creation errors more robustly

We have seen strange cases where creation of a new CIB object apparently
failed:

  http://pastebin.suse.de/9346

Even though this is strange, we should certainly expect
Pacemaker::CIBObject.from_name to return nil in a few cases, so we need
to handle that properly.
guard mixins properly
Merge pull request #38 from aspiers/guard-mixins

guard mixins properly
Merge pull request #29 from aspiers/hb-gui-fixes

hb_gui tweaks
Merge pull request #37 from aspiers/create-resource-check

handle creation errors more robustly
Split out haproxy recipe in crowbar-pacemaker

No code change, but we have a better split of the code.
Only load crm-initial.conf when the file got changed

There is no point in loading it if it's the same as before, since we
already imported these settings.
Make stonith-enabled/no-quorum-policy variables in crm-initial.conf

The values will change depending on options in the wrapper, or other
factors.
Add a STONITH recipe

By default, STONITH is marked as disabled. It can be enabled and
configured:

 - manually (by the user)
 - with a stonith plugin that will be used with a clone resource
 - with a stonith plugin that will have per-node parameters
Check that the specified STONITH plugin is available

We simply need to check if the plugin is in the output of "stonith -L".
Compute no-quorum-policy based on number of members in the cluster

This is "ignore" if we have 1 or 2 members, and "stop" (the default) for
more members.

We do this magic in the crowbar-pacemaker cookbook, since we have the
required information there.
Add support for IPMI as STONITH in crowbar-pacemaker

Since Crowbar can know about IPMI configuration of nodes, we can
translate this into a valid STONITH configuration.
Add support for using libvirt STONITH plugin in crowbar-pacemaker

For development purposes, it's very useful to be able to simply use the
external/libvirt STONITH plugin. It turns out that we only need to be
aware of the hypervisor IP address; all the other information we can
find through node attributes.

Useful resource:
http://www.hastexo.com/resources/hints-and-kinks/fencing-libvirtkvm-virtualized-cluster-nodes
Add attributes and barclamp webui for STONITH
Add validation for stonith bits of the proposal