Fix shell reporter running even when diff is empty (#837)

Author: MarcPer

lib/urlwatch/reporters.py

@@ -1113,12 +1113,14 @@ class ShellReporter(TextReporter):
     __kind__ = 'shell'
 
     def submit(self):
-        text = '\n'.join(super().submit()) + '\n'
+        text = '\n'.join(super().submit())
 
         if not text:
             logger.debug('Not calling shell reporter (no changes)')
             return
 
+        text = text + '\n'
+
         cmd = self.config['command']
 
         process = subprocess.Popen(cmd, stdin=subprocess.PIPE, stdout=subprocess.PIPE, stderr=subprocess.PIPE)