netinfo: Make bonding functions private and move them before _getNetInfo

This is a cleanup after merging just two bondopts patches.
One of the unmerged patches, whose purpose was to reset
a bond’s options to default values, needed the functions
to be public.

Change-Id: I6df1820a8a3e854de42559cb06b2b43eb01bd481
Signed-off-by: Ondřej Svoboda <osvoboda@redhat.com>
Reviewed-on: http://gerrit.ovirt.org/28810
Reviewed-by: Antoni Segura Puimedon <asegurap@redhat.com>
Reviewed-by: Dan Kenigsberg <danken@redhat.com>