CONTROLLER-1809: De-deplicate extraneous ManagedService updates

CONTROLLER-1809: De-deplicate extraneous ManagedService updates

For some strange reason, the ComponentProcessor gets an extraneous
duplicate update from the ConfigAdmin when running the netvirt
integration/CSIT which causes it to restart the container b/c it
thinks there was an update. There is no cfg file so both updates
pass a null Properties. Oddly, I do not see this behavior when
installing the toaster feature from the controller karaf.

I added logic to store the last update and only restart if it
changed. In my testing though, the ConfigAdmin does not notify
unless a change actually occurred.

Change-Id: I692dbd7fcaf921b90f828059d6104138c16a0508
Signed-off-by: Tom Pantelis <tompantelis@gmail.com>