deserialize does not work for functions outside of a module

[ardunn]

To reproduce:

1. move an example outside the package
2. rename the example (so it doesn't just call the functions in the package)
3. get_z (and possibly wf_creator) fails:

Traceback (most recent call last):
  File "complex2.py", line 126, in <module>
    get_z=get_z,
  File "/home/x/down/tenv/lib/python3.6/site-packages/rocketsled/control.py", line 228, in configure
    config[kw] = serialize(kwargs[kw])
  File "/home/x/down/tenv/lib/python3.6/site-packages/rocketsled/utils.py", line 132, in serialize
    full_import_path = all_pkgs[-1] + mod_sep + full_import_path
IndexError: list index out of range