datapath/loader: carry on on failure to set up transient iptables rules
datapath/loader: carry on on failure to set up transient iptables rules

When Reinitialize()-ing the datapath, transient iptables rules are set
up to avoid dropping packets while Cilium's rules are not in place.

In rare occasions, a failure to add those rules has been observed (see
issue #11276), leading to an early exit from Reinitialize() and a
failure to set up the daemon.

But those transient rules are just used to lend a hand and keep packets
going for a very small window of time: it does not actually matter much
if we fail to install them, and it should not stop the reinitializing of
the daemon. Let's simply log a warning and carry on if we fail to add
those rules.

Signed-off-by: Quentin Monnet <d6b8e48afb2534b213e391cab43016505747a234@isovalent.com>

tgraf/cilium,cilium/cilium,tklauser/cilium,cilium/cilium,tgraf/cilium,tklauser/cilium,michi-covalent/cilium,tklauser/cilium,tgraf/cilium,tklauser/cilium,tgraf/cilium,michi-covalent/cilium,cilium-team/cilium,cilium/cilium,tklauser/cilium,cilium/cilium,michi-covalent/cilium,cilium-team/cilium,tgraf/cilium,michi-covalent/cilium,tgraf/cilium,cilium/cilium,michi-covalent/cilium