Sync excutils from Oslo

This patch adds the excutils module to openstack-common.conf,
sync excutils from oslo-incubator and uses save_and_reraise_exception
where it is relevant.

Change-Id: Id190aad9a4fd2dd7bf962f001f88b6a0884c18a1
oslo.vmware refactoring

Change-Id: I121204e40114c64994a1002a9c6bb983a4dffcd5