TT#36053 Stop sems* with -KILL

Otherwise it refuses to stop, until it reaches the timeout.

Confirmed that it's OK to kill in this way, and waiting for implementation
changes so this is not necessary.

Change-Id: I34fc0b017b17779e8a15e031bf78960bbca2ada7

debian/ngcp-sems.service

@@ -18,6 +18,7 @@ PassEnvironment=LD_LIBRARY_PATH
 PIDFile=/run/ngcp-sems/ngcp-sems.pid
 Restart=always
 ExecStart=/usr/sbin/ngcp-sems -E -u sems -g sems -P /run/ngcp-sems/ngcp-sems.pid -f /etc/ngcp-sems/sems.conf
+ExecStop=/bin/kill -KILL $MAINPID
 TimeoutStopSec=10
 LimitNOFILE=100000