Unified validators
Unified validators

When parameter value should not be empty, user has to explicitly use validate_not_empty
validator. Some validators did not follow this rule. This patch is fixing it.

Change-Id: I92fb0773a2bc69fe05f79ba03dd487b15da5d9c6

openstack/packstack,palmer159/openstack-test,fr34k8/packstack,openstack/packstack,openstack/packstack,stackforge/packstack,fr34k8/packstack,palmer159/openstack-test,mahak/packstack,imcsk8/packstack,xbezdick/packstack,xbezdick/packstack,imcsk8/packstack,palmer159/openstack-test,mahak/packstack,stackforge/packstack,stackforge/packstack,mahak/packstack,fr34k8/packstack,imcsk8/packstack,xbezdick/packstack