When checking for empty sequences

[rasmunk]

https://github.com/rasmunk/docker-migrid/blob/9b8b092f1eb1d7117088a19fe8e0a48bd740fcd4/mig/shared/pattern.py#L70

As per https://www.python.org/dev/peps/pep-0008/

For sequences, (strings, lists, tuples), use the fact that empty sequences are false.

` Yes: if not seq: if seq:

No: if len(seq): if not len(seq):`

You can improve both L70 and L57 with:

`if not self.trigger_paths:

....

`

[rasmunk]

As per the refactor this is no longer an issue