[SpecFile.reload()] don't _read_spec_content() before update()

The SpecContent instance which _read_spec_content() returns
is thrown away so the call is useless.
update() calls it too, but saves the instance to self.spec_content

rebasehelper/specfile.py

@@ -996,7 +996,6 @@ def copy(self, new_path):
 
     def reload(self):
         """Reloads the whole Spec file."""
-        self._read_spec_content()
         self.update()
 
     def save(self):