control: Rework/optimize preloading timer groups

Employ the use of the service name defined on the group instead of
retrieving the service for each group member if its given in the group's
configuration. In addition, switch to getting the service, when not
configured on the group, from the service tree cache.

Change-Id: Ice7b19c90c8fc03cb7201ebdb884c23366c1f23e
Signed-off-by: Matthew Barth <msbarth@us.ibm.com>
1 file changed