Add pid file of fai-monitor

porch/api/machine/bizlogic.py

@@ -448,7 +448,8 @@ def install_machine(data):
     return (True, s_date)
 
 def _bgmonitorprocess(i_port, s_logfile):
-    s_cmd = "sudo {} -d -p {} -l {} -T".format(FAI_MONITOR, i_port, s_logfile)
+    s_cmd = "sudo {} -d  -p {} -l {} -T -P /tmp/{}.pid"\
+            .format(FAI_MONITOR, i_port, s_logfile, i_port)
     log.debug(s_cmd)
     with open(s_logfile, 'w+') as f:
         proc = Popen(s_cmd, shell=True, stdout=f, stderr=f)