virt: split CPU spec parsing code out into helper method

The get_vcpu_pin_set method in nova.virt.hardware will
parse the value of the CONF.vcpu_pin_set parameter. The
code for parsing CPU specs is needed in a number of other
contexts, so split it into a separate parse_cpu_spec
method that accepts a string, instead of hardcoding the
CONF.vcpu_pin_set string.

Blueprint: virt-driver-numa-placement
Blueprint: virt-driver-cpu-pinning
Change-Id: Ia9df3a7bebd691efc2143e141b2c6eef2f1c326c
vmwareapi: make method signatures match parent class

Fix any inconsistencies in method signatures between the
vmwareapi driver impl and the ComputeDriver parent class.
Add a test case to prevent future regressions

Closes-bug: #1333219
Change-Id: Ic361a922a1aefa5b5a3470c0547e694d073d2d58
Merge "vmwareapi: make method signatures match parent class"
Merge "virt: split CPU spec parsing code out into helper method"