Make nova patching parameters configurable in Nuage

Make nova patching parameters configurable in Nuage

Nova patching parameters are available in nova.conf but are not
configurable from tripleo-heat-templates. Exposing these parameters
from Nuage composable services to make them configurable. It enables
setting the patching parameters in environment files. This change
depends on the addition of nova patching configuration parameters.

Change-Id: Iacad25da044f2bac83ee5f577ddcd70650eb61e5
Depends-On: I51ef3e19daff1d98cfe5c2c16475c16e6a3e3e0f
(cherry picked from commit f0041153eca8d82bb7f72dc68676cab8448ef037)