[services] Remove explicit dependencies from dhcp_relay service file, control in swss.sh (sonic-net#3823)

Author: jleveque

files/build_templates/dhcp_relay.service.j2

@@ -1,6 +1,6 @@
 [Unit]
 Description=DHCP relay container
-Requires=updategraph.service swss.service teamd.service
+Requires=updategraph.service
 After=updategraph.service swss.service syncd.service teamd.service
 Before=ntp-config.service
 StartLimitIntervalSec=1200
@@ -15,4 +15,4 @@ Restart=always
 RestartSec=30
 
 [Install]
-WantedBy=multi-user.target swss.service teamd.service
+WantedBy=multi-user.target

files/scripts/swss.sh

@@ -2,7 +2,7 @@
 
 SERVICE="swss"
 PEER="syncd"
-DEPENDENT="teamd radv"
+DEPENDENT="teamd radv dhcp_relay"
 DEBUGLOG="/tmp/swss-syncd-debug.log"
 LOCKFILE="/tmp/swss-syncd-lock"