[PATCH] bonding: Fix primary selection error at enslavement time

	At enslavement time, the primary slave might not be activated if
there is already an active slave and the new slave is the primary.
Replaced complicated logic with a call to bond_select_active_slave(),
which does the right thing.

	Fixes http://bugzilla.kernel.org/show_bug.cgi?id=6378

Signed-off-by: Jay Vosburgh <fubar@us.ibm.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>