Last,fm Loved Tracks plugin fails on unload

[Rocco Aliberti]

rev3812

Little bug (a typo, i think) if you unload that plugin before really using it.

Traceback (most recent call last):
  File "/usr/lib64/exaile/xl/plugins.py", line 138, in disable_plugin
    plugin.disable(self.exaile)
  File "/usr/share/exaile/plugins/lastfmlove/__init__.py", line 63, in disable
    LASTFMLOVER.destroy()
  File "/usr/share/exaile/plugins/lastfmlove/__init__.py", line 198, in destroy
    if self.timer.is_alive():
AttributeError: 'NoneType' object has no attribute 'is_alive'

Patch attached.

[Mathias Brodala (mathbr)]

Fixed with r3813, thanks.