vswitch: Correctly identify slave status in /proc compatibility layer

vswitch: Correctly identify slave status in /proc compatibility layer

In the /proc compatibility layer, the bond member was reported as up
immediately after link recovery, regardless of the updelay.  I believe
the compatibility code was correct if the check had been done with carrier,
but since 'iface->enabled' already does that calculation, we can use it
directly.

Additinally, when a bond slave was enabled or disabled, the bond
compatibility code was not being told to update its state.  This commit
makes that call.

NIC-39