stack/monitor: Fix promise for the running process

  Kill -0 were making the promise exit.

stack/monitor/buildout.cfg

@@ -93,7 +93,7 @@ recipe = slapos.recipe.template:jinja2
 filename = template-monitor.cfg
 template = ${:_profile_base_location_}/instance-monitor.cfg.jinja2.in
 rendered = ${buildout:directory}/template-monitor.cfg
-md5sum = 0955530291105a322f2972244caf307d
+md5sum = 266f23bc836a938ac69ce0bc674f34fe
 context =
     key apache_location apache:location
     key gzip_location gzip:location

stack/monitor/instance-monitor.cfg.jinja2.in

@@ -373,16 +373,14 @@ check-secure = 1
 recipe = collective.recipe.template
 file = ${monitor-conf-parameters:promise-output-file}
 input = inline:#!{{ dash_executable_location }}
-  if [ -f "${monitor-conf-parameters:pid-file}" ]; then
-    PID=`cat ${monitor-conf-parameters:pid-file}`
+  pidfile=${monitor-conf-parameters:pid-file}
+  COMMAND=monitor.bootstrap
+  if [ -s $pidfile ]; then
     for i in {1..20}; do
-      # wait for monitor bootstrap script to finish (max 10 seconds)
-      kill -0 "$PID" > /dev/null 2>&1
-      RETURN_CODE=$?
-      if [ $RETURN_CODE -eq 0 ] ; then
-        break
-      else
+      if pid=`pgrep -F $pidfile -f "$COMMAND" 2>/dev/null`; then
         sleep 0.5
+      else
+        break
       fi
     done
   fi