Add conditional skips for nova jobs
Add conditional skips for nova jobs

THis change uses skip-if to avoid running
{devstack,grenade-tempest}-dsvm jobs when the files in the patchset are
deemed to not influence their execution.

Another skip-if filter avoids running non-doc jobs against doc-only nova
changes.

Based on: I638ac2d35c33eef02e2c6872ea3bd4a3d644da58

Change-Id: Id3ccf3affdcbfc2da4571557957f6f3c284fdcee

citrix-openstack/project-config,citrix-openstack/project-config,Tesora/tesora-project-config,dongwenjuan/project-config,coolsvap/project-config,anbangr/osci-project-config,anbangr/osci-project-config,openstack-infra/project-config,open-switch/infra_project-config,open-switch/infra_project-config,Tesora/tesora-project-config,openstack-infra/project-config,coolsvap/project-config,noorul/os-project-config,noorul/os-project-config,dongwenjuan/project-config