Fix runing veles from python2

[Lyubava]

lpodoynitsina@lpodoynitsinau64:~/Projects/Veles$ python
Python 2.7.6 (default, Jun 22 2015, 17:58:13)
[GCC 4.8.2] on linux2
Type "help", "copyright", "credits" or "license" for more information.

import veles
veles/init.py:67: UserWarning: Cannot expand variables generated by Git, setting them to None
warn("Cannot expand variables generated by Git, setting them to None")
kwargs={"dry_run": "init", "snapshot": file_name, "stealth": True}
Traceback (most recent call last):
File "", line 1, in
NameError: name 'file_name' is not defined
kwargs={"dry_run": "init", "stealth": True}
path_to_model = "veles/znicz/samples/MNIST/mnist.py"
launcher = veles(path_to_model, **kwargs)
Traceback (most recent call last):
File "", line 1, in
File "veles/init.py", line 179, in call
Main = import_module("veles.main").Main
TypeError: 'NoneType' object is not callable