core: Fixing PM options caching

fencingOptionMapping cache map was declared as static
as a result if it was initialized once with the 'general' version
the values of this version was used for all instances no matter which
version is given to the constructor.
This eliminates new agents added in later versions to function and
display supported port/slot/secure fields correctly

Change-Id: I03e4a98919105bbb0d7ef382234b8810db044215
Bug-Url: https://bugzilla.redhat.com/show_bug.cgi?id=1020344
Signed-off-by: Eli Mesika <emesika@redhat.com>