lacp: Loosen lacp_slave_is_current().

lacp: Loosen lacp_slave_is_current().

The lacp_slave_is_current() function is used to indicate to a
controller failover status of the LACP module.  However, the result
of this function is more strict than the failover logic.  Thus, the
function will generally return false quite a bit before a failover
actually happens.  This patch loosens lacp_slave_is_current() so
that it changes in-line with the failover logic.