core: Remove GetAgentFenceOptions2Query

GetAgentFenceOptionsQuery and GetAgentFenceOptions2Query are completely
identical except for the usage of different APIs of VdsFenceOptions.

Since GetAgentFenceOptions is not used anywhere, it is removed, and
GetAgentFenceOptions2 loses it "2" and get a name the better suits
conventions (not to mention common sense).

This patch includes:
1. Removing the old GetAgentFenceOptionsQuery class and renaming
   GetAgentFenceOptions2Query to take its place.
2. Removing the old GetAgentFenceOptions constant in the VdsQueryTye
   enum, and renaming GetAgentFenceOptions2 to take its place.
3. Clearing up the VdsFenceOptions class from methods with "2" in their
   name - either by removing unused methods, or by renaming them to a
   more sensible name.

Change-Id: Id2d7f15c16257f39f162b52d22f7c2faf8eb291a
Signed-off-by: Allon Mureinik <amureini@redhat.com>