Fixes #9858: When upgrading Rudder, we get mails from cron saying \"o…

…k: Rudder agent check ran without errors.\"

rudder-agent/SOURCES/rudder-agent-postinst

@@ -120,12 +120,12 @@ fi
 
 # Add temporary cron for checking UUID. This cron is created in postinst
 # in order to remove it later without complains of the package manager.
-CHECK_RUDDER_AGENT_CRON=`grep "/opt/rudder/bin/check-rudder-agent" /etc/cron.d/rudder-agent | wc -l`
+CHECK_RUDDER_AGENT_CRON=`grep -E "agent check|check-rudder-agent" /etc/cron.d/rudder-agent | wc -l`
 TMP_CRON=/etc/cron.d/rudder-agent-uuid
 # Add it only if the default cron file does not call check-rudder-agent script
 if [ ${CHECK_RUDDER_AGENT_CRON} -eq 0 ]; then
   if [ ! -f ${TMP_CRON} ]; then
-    echo "0,5,10,15,20,25,30,35,40,45,50,55 * * * * root ${RUDDER_CMD} agent check" > ${TMP_CRON}
+    echo "0,5,10,15,20,25,30,35,40,45,50,55 * * * * root ${RUDDER_CMD} agent check > /dev/null" > ${TMP_CRON}
   fi
 fi