Span objects do not need to have multiple possible parents.
Span objects do not need to have multiple possible parents.

Change-Id: I599da671764a7df93d4770e2d0451a3fef75995d
Signed-off-by: Tom Flynn <abc7c57a6537c493534eb3847500f37bef7b716d@gmail.com>

opendaylight/opflex,opendaylight/opflex,opendaylight/opflex,opendaylight/opflex