TT#36043 Switch Requires=monit.service to Wants=monit.service for heartbeat

Heartbeat doesn't depends on monit anymore since mr6.2+.
HA uses ngcp-service and ngcp-service calls systemctl directly to
wait for services to be up and ready. It allows to handle services
dependencies properly. ngcp-service also calls 'monit monitor/unmonitor'
while it should work well with Wants=monit.service, in the worst case
the monit on active node will show 'Not monitored' for already running
services. It is a price for keeping HA running on monit service restart.

The price is acceptable here as we are going to remove monit anyway and
'ngcp-service summary' output is already reliable here for all the
corner cases.

Change-Id: I9060ca63ac0e7aceadf045f6f4465811f3c595ad

debian/heartbeat-2.heartbeat.service

@@ -1,12 +1,12 @@
 [Unit]
 Description=Heartbeat subsystem for High-Availability Linux
 Documentation=man:heartbeat(8)
-Requires=monit.service
 After=monit.service
 After=network-online.target
 After=time-sync.target
 After=openhpid.service
 Wants=network-online.target
+Wants=monit.service
 
 [Service]
 Type=forking