Add small improvements to the compute nodes

[Vladimir Kuklin]

Just sitting next to screaming SuperMicro, I remembered a couple of
cpu optimizations I did nearly a year ago to improve KVM guests
performance:

intel_idle.max_cstate=0 processor.max_cstate=0 for kernel

coupled with switch to the performance governor. I`m in doubt if we
need to push governor "strict switch" to the OS or just implement it
in the FUEL. Disabling of Intel cstates is another task which cannot
be done without reboot as far as I know but greatly improves speed of
hvm guests such as Windows. So another question is about introducing
this optimization (and reboot of compute in the middle and higher
electricity taxes for end-user) or just mention it in the docs.

[Andrey Korolyov (xdeller)]

https://github.com/Mirantis/fuel/pull/782
https://review.openstack.org/#/c/55526/

[Mike Scherbakov (mihgen)]

https://github.com/Mirantis/fuel/pull/782 is wrong pull request. Can not find your code piece in master branch. Please verify.

[Mike Scherbakov (mihgen)]

Valid pull request found, on review: https://github.com/Mirantis/fuel/pull/856/files