server: Ignore mapper generated signals
server: Ignore mapper generated signals

Correct a bug that prevented this.  This was always the intent as
the mapper does not rely on dbus to inform it of its own
signal generating actions.

Change-Id: I56af68ed65903ac105a6fb553010c389cf0ea679
Signed-off-by: Brad Bishop <713d098c0be4c8fd2bf36a94cd08699466677ecd@fuzziesquirrel.com>

openbmc/phosphor-objmgr,openbmc/phosphor-objmgr