core:  PRD32 - RFE: Multi-Tier fencing in RHEV-M

1) Removing the status check in the canDoAction such that for sequential
multiple agents secondary agent will still be used even tough the
primary agent is not reachable.
Also added an Alert in case that a primary agent failed to function and
a secondary agent is used in the case of sequential multiple agents.

Change-Id: Ieb5a3a8edeb58f74f0e74d3e54911f0cdb614762
Bug-Url: https://bugzilla.redhat.com/show_bug.cgi?id=773108
Signed-off-by: Eli Mesika <emesika@redhat.com>