bonding: "primary_reselect" with "failure" is not working properly

When "primary_reselect" is set to "failure", primary interface should
not become active until current active slave is down. But if we set first
member of bond device as a "primary" interface and "primary_reselect"
is set to "failure" then whenever primary interface's link get back(up)
it become active slave even if current active slave is still up.

With this patch, "bond_find_best_slave" will not traverse members if
primary interface is not candidate for failover/reselection and current
active slave is still up.

Signed-off-by: Mazhar Rana <mazhar.rana@cyberoam.com>
Signed-off-by: Jay Vosburgh <j.vosburgh@gmail.com>
Signed-off-by: Jay Vosburgh <jay.vosburgh@canonical.com>
Signed-off-by: David S. Miller <davem@davemloft.net>