monitor: bootstrap promise don't fail if pid file doesn't exists

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 = c25e1c8206fb7c08924ae3d5c16521fc
+md5sum = 61734742e3a01a8a1d512f491b2190cc
 context =
     key apache_location apache:location
     key gzip_location gzip:location

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

@@ -372,17 +372,19 @@ check-secure = 1
 recipe = collective.recipe.template
 file = ${monitor-conf-parameters:promise-output-file}
 input = inline:#!{{ dash_executable_location }}
-  PID=`cat ${monitor-conf-parameters:pid-file}`
-  for i in {1..20}; do
-    # wait for monitor bootstrap script to finish (max 10 seconds)
-    kill -0 "$PID" > /dev/null 2>&1
-    RETURN_CODE=$?
-    if [ $RETURN_CODE -eq 0 ] ; then
-      break
-    else
-      sleep 0.5
-    fi
-  done
+  if [ -f "${monitor-conf-parameters:pid-file}" ]; then
+    PID=`cat ${monitor-conf-parameters:pid-file}`
+    for i in {1..20}; do
+      # wait for monitor bootstrap script to finish (max 10 seconds)
+      kill -0 "$PID" > /dev/null 2>&1
+      RETURN_CODE=$?
+      if [ $RETURN_CODE -eq 0 ] ; then
+        break
+      else
+        sleep 0.5
+      fi
+    done
+  fi
   if [ ! -f "${:file}" ]; then echo "Monitor bootstrap exited with error." && exit 2; else echo "Bootstrap OK"; fi
 output = ${directory:promises}/monitor-bootstrap-status
 mode = 700