ifupdown2: mstpctl: check mstpd running just once during init of mstpctl modules

Ticket: CM-8035
Reviewed By: wkok
Testing Done: Tested mstp commands in interfaces file

(cherry picked from commit 2c3471f2082c8adbdcc395cbd0066680f280b9e5)

ifupdownaddons/systemutils.py

@@ -42,3 +42,15 @@ class systemUtils():
             # XXX: check for subprocess errors vs os error
             return False
         return True
+
+    @classmethod
+    def is_process_running(self, processname):
+        if not processname:
+            return False
+        utilsobj = utilsBase()
+        try:
+            utilsobj.exec_command('/bin/pidof %s' %processname)
+        except:
+            return False
+        else:
+            return True