Fix usage of psutil
Fix usage of psutil

Psutil.error is an internal class and shouldn't be referenced from
outside as per https://code.google.com/p/psutil/issues/detail?id=246



Fixes #760
ettrig/NIPAP,fredsod/NIPAP,fredsod/NIPAP,fredsod/NIPAP,bbaja42/NIPAP,SpriteLink/NIPAP,bbaja42/NIPAP,SpriteLink/NIPAP,SoundGoof/NIPAP,garberg/NIPAP,bbaja42/NIPAP,bbaja42/NIPAP,garberg/NIPAP,garberg/NIPAP,bbaja42/NIPAP,SpriteLink/NIPAP,SoundGoof/NIPAP,ettrig/NIPAP,bbaja42/NIPAP,ettrig/NIPAP,SoundGoof/NIPAP,fredsod/NIPAP,garberg/NIPAP,SpriteLink/NIPAP,SpriteLink/NIPAP,SpriteLink/NIPAP,ettrig/NIPAP,ettrig/NIPAP,ettrig/NIPAP,fredsod/NIPAP,SoundGoof/NIPAP,fredsod/NIPAP,SoundGoof/NIPAP,garberg/NIPAP,garberg/NIPAP,SoundGoof/NIPAP