openvswitch: Fix helper reference leak

openvswitch: Fix helper reference leak

[ Upstream commit 2f3ab9f9fc23811188b9d07d86e4d99ffee887f4 ]

If the actions (re)allocation fails, or the actions list is larger than the
maximum size, and the conntrack action is the last action when these
problems are hit, then references to helper modules may be leaked. Fix
the issue.

Fixes: cae3a2627520 ("openvswitch: Allow attaching helpers to ct action")
Signed-off-by: Joe Stringer <joe@ovn.org>
Acked-by: Pravin B Shelar <pshelar@nicira.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>