Fixed search results totals

Fixes:

INFO:spotify.session:Logged in
spotify> search blur
spotify> Exception in thread Thread-1:
Traceback (most recent call last):
  File "/usr/lib/python2.7/threading.py", line 552, in __bootstrap_inner
    self.run()
  File "shell.py", line 137, in run
    stop = action(*args)
  File "shell.py", line 207, in do_search
    result.artists_total, result.playlist_total)
AttributeError: 'Search' object has no attribute 'artists_total'