Allow ValueError as a notify exception

[p-mongo]

I was getting this:

averagest% python3 -m scudcloud            
Traceback (most recent call last):
  File "/usr/lib/python3.6/runpy.py", line 193, in _run_module_as_main
    "__main__", mod_spec)
  File "/usr/lib/python3.6/runpy.py", line 85, in _run_code
    exec(code, run_globals)
  File "/home/w/apps/exp/scudcloud/scudcloud/__main__.py", line 16, in 
    import scudcloud.scudcloud as sca
  File "/home/w/apps/exp/scudcloud/scudcloud/scudcloud.py", line 3, in 
    from scudcloud.notifier import Notifier
  File "/home/w/apps/exp/scudcloud/scudcloud/notifier.py", line 4, in 
    gi.require_version('Notify', '0.7')
  File "/usr/lib/python3/dist-packages/gi/__init__.py", line 130, in require_version
    raise ValueError('Namespace %s not available' % namespace)
ValueError: Namespace Notify not available

Adding ValueError to the list of allowed exceptions made the program start.

[raelgc]

Thanks @p-mongo!