This patch switches over to callback payloads for SECURITY_GROUP
events. To do so a few shims are put into place the handle both
payload and kwarg style callbacks; these shims will be removed once
all events use payloads. In addition a few UT updates are included to
get the tests working properly with payloads.
Change-Id: I6161a8b387812808c4d679f882a3193c93235647