ovn-macros: Make sure stopped daemons continue before the test ends.

In case there's a test failure while daemons are stopped ensure that we
send a SIGCONT on exit so that they properly clean up.

Fixes: 30952c2 ("binding: fixed ovn-installed not properly removed (recomputes)")
Fixes: 0794a6e ("qos: fix potential double deletion of ovs idl row")
Fixes: feb9184 ("northd: Skip transient IDL records.")
Suggested-by: Ilya Maximets <i.maximets@ovn.org>
Signed-off-by: Dumitru Ceara <dceara@redhat.com>
Acked-by: Xavier Simonart <xsimonar@redhat.com>

tests/ovn-macros.at

@@ -894,6 +894,7 @@ start_scapy_server() {
 sleep_northd() {
   echo Northd going to sleep
   AT_CHECK([kill -STOP $(cat northd/ovn-northd.pid)])
+  on_exit "kill -CONT $(cat northd/ovn-northd.pid)"
 }
 
 wake_up_northd() {
@@ -904,6 +905,7 @@ wake_up_northd() {
 sleep_sb() {
   echo SB going to sleep
   AT_CHECK([kill -STOP $(cat ovn-sb/ovsdb-server.pid)])
+  on_exit "kill -CONT $(cat ovn-sb/ovsdb-server.pid)"
 }
 wake_up_sb() {
   echo SB waking up
@@ -927,6 +929,7 @@ sleep_ovs() {
   hv=$1
   echo ovs $hv going to sleep
   AT_CHECK([kill -STOP $(cat $hv/ovs-vswitchd.pid)])
+  on_exit "kill -CONT $(cat $hv/ovs-vswitchd.pid)"
 }
 
 wake_up_ovs() {
@@ -938,6 +941,7 @@ wake_up_ovs() {
 sleep_ovsdb() {
   echo OVSDB $1 going to sleep
   AT_CHECK([kill -STOP $(cat $1/ovsdb-server.pid)])
+  on_exit "kill -CONT $(cat $1/ovsdb-server.pid)"
 }
 wake_up_ovsdb() {
   echo OVSDB $1 waking up