CC-4092: Not checking for return type "None" on some function calls in media-monitor

-fixed

python_apps/media-monitor/airtimefilemonitor/airtimemediamonitorbootstrap.py

@@ -117,10 +117,9 @@ class AirtimeMediaMonitorBootstrap():
         stdout = self.mmc.exec_command(command)
         
         if stdout is None:
-            self.logger.error("Unrecoverable error when syncing db to filesystem.")
-            return
-
-        new_files = stdout.splitlines()
+            new_files = []
+        else:
+            new_files = stdout.splitlines()
 
         new_and_modified_files = set()
         for file_path in new_files:

python_apps/media-monitor/airtimefilemonitor/mediamonitorcommon.py

@@ -291,7 +291,10 @@ class MediaMonitorCommon:
         self.logger.debug(command)
         stdout = self.exec_command(command)
 
-        return stdout.splitlines()
+        if stdout is None:
+            return []
+        else:
+            return stdout.splitlines()
 
     def touch_index_file(self):
         dirname = os.path.dirname(self.timestamp_file)