post-v1.5.0
------------------------
+ - bonding
+ - LACP bonds no longer fall back to balance-slb when negotiations fail.
+ Instead they drop traffic.
+ - The default bond_mode changed from SLB to active-backup, to protect
+ unsuspecting users from the significant risks of SLB bonds (which are
+ documented in vswitchd/INTERNALS).
v1.5.0 - xx xxx xxxx