Collect corosync-cfgtool -s output and added Pacemaker support

This patch improves HA clustering information gathering adding a new a
new plugin for Pacemaker.

Here is a portion of the list of files that were included in a report generated with this change:

```
...
 -rw-r--r--    root/root        116 sosreport-freyes-local-machine-3.1234-20141118160449/sos_commands/corosync/corosync-cfgtool_-s
 drwx------    root/root          0 sosreport-freyes-local-machine-3.1234-20141118160449/sos_commands/pacemaker/
 -rw-r--r--    root/root        467 sosreport-freyes-local-machine-3.1234-20141118160449/sos_commands/pacemaker/crm_status
 -rw-r--r--    root/root        532 sosreport-freyes-local-machine-3.1234-20141118160449/sos_commands/pacemaker/crm_configure_show
...
 drwxr-xr-x    root/root          0 sosreport-freyes-local-machine-3.1234-20141118160449/var/lib/pacemaker/
 drwxr-xr-x    root/root          0 sosreport-freyes-local-machine-3.1234-20141118160449/var/lib/pacemaker/cib/
 -rw------- hacluster/haclient    1943 sosreport-freyes-local-machine-3.1234-20141118160449/var/lib/pacemaker/cib/cib.xml
...
```