sensors_temperature() on Linux may raise IO error

[giampaolo]

 2017-04-08 20:04:09,503 -- ERROR -- Traceback (most recent call last):
   File "/usr/local/lib/python2.7/dist-packages/glances/stats.py", line 105, in _load_plugin
     self._plugins[name] = plugin.Plugin(args=args)
   File "/usr/local/lib/python2.7/dist-packages/glances/plugins/glances_sensors.py", line 53, in __init__
     self.glancesgrabsensors = GlancesGrabSensors()
   File "/usr/local/lib/python2.7/dist-packages/glances/plugins/glances_sensors.py", line 231, in __init__
     self.stemps = psutil.sensors_temperatures()
   File "/usr/local/lib/python2.7/dist-packages/psutil/__init__.py", line 2212, in sensors_temperatures
     rawdict = _psplatform.sensors_temperatures()
   File "/usr/local/lib/python2.7/dist-packages/psutil/_pslinux.py", line 1116, in sensors_temperatures
     current = float(cat(base + '_input')) / 1000.0
   File "/usr/local/lib/python2.7/dist-packages/psutil/_pslinux.py", line 299, in cat
     return f.read().strip()
  IOError: [Errno 5] Input/output error

See: nicolargo/glances#1079