WindowsError is a subclass of OSError and need not be excepted

This fixes bug 2254: https://code.google.com/p/sickbeard/issues/detail?id=2254
Prevent NameError on Linux
Bugfix :: loadFromTVDB : Prevents corrupted data from TheTVDB
tv_shows.show_name in sickbeard.db can never be a NoneType. Patch prevents this from happening if someone has removed the seriesname attribute in the TVDB show entry.
Bugfix :: tvrage.py : Handle "No Show Found" on TVRage.
Merge pull request #682 from Conjuro/TVRage-No_show

Bugfix :: tvrage.py : Handle "No Show Found" on TVRage.
Merge pull request #681 from Conjuro/Bugfix-show_name-None

Bugfix :: loadFromTVDB : Prevents corrupted data from TheTVDB
Merge pull request #654 from depassp/bug-2254

WindowsError is a subclass of OSError and need not be excepted