core: fence_apc_snmp VdsFenceOptionMapping uses ...

fence_apc_snmp VdsFenceOptionMapping uses unsupported secure option

Removing unsupported "secure" and "slot" option from VdsFenceOptionMapping for the
apc_snmp agent in versions 3.2 and 3.3

Change-Id: I6b6811d6a434654936f6736a9c791fb5fb04437b
Bug-Url: https://bugzilla.redhat.com/show_bug.cgi?id=1001115
Signed-off-by: Eli Mesika <emesika@redhat.com>