policy: Clarify locking.
policy: Clarify locking.

Take the repo revision after acquiring the lock on the cached
policy. This does not change anything as the repo is read locked, but
makes this more obviously correct.

Signed-off-by: Jarno Rajahalme <0f1ab0ac7dffd9db21aa539af2fd4bb04abc3ad4@covalent.io>

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