Add skip if for tempest running tempest on tempest commits
Add skip if for tempest running tempest on tempest commits

This commit adds a skipIf check for running tempest jobs on specific
tempest commits. If the proposed commit is a doc only, or a sample
config only change there is no need to run the tempest tests on the
commit.

Change-Id: I664288625727a19edcba6b19343d4dd9762f86dd

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