ability to resolve any kind of volume path to the pool target volume
path.  For instance, if the pool was defined with a
<target><path>/dev/disk/by-id</path></target> section, and one of the
volumes is /dev/disk/by-id/scsi-S_beaf11, then you would be able to
call virStorageVolLookupByPath("/dev/sdc"), and get the correct volume
back.
Signed-off-by: NChris Lalancette <clalance@redhat.com>