Move rng device checks to the appropriate method
Move rng device checks to the appropriate method

It seems that during refactoring the code related to rng device ended up
in the wrong method. This change moves the code to the method that
actually handles rng device. The behavior does not change, the change is
only cosmetic.

Change-Id: I1473c8d55b0ecfa33d432b409e651d933f5947a5

openstack/nova,rahulunair/nova,mahak/nova,rahulunair/nova,openstack/nova,openstack/nova,rahulunair/nova,klmitch/nova,mahak/nova,klmitch/nova,klmitch/nova,mahak/nova,klmitch/nova