Correct _poolPubKey to _poolId

This was somehow missed in #1945, and for some (unknown to me) reason,
CI didn't pick up on it. But when I try to build, it fails.

Regardless, this should be fixed!

shelley/chain-and-ledger/executable-spec/src/Shelley/Spec/Ledger/Rewards.hs

@@ -533,7 +533,7 @@ nonMyopicMemberRew
   t
   topPools
   (PerformanceEstimate p) =
-    let nm = nonMyopicStake pp s sigma t (_poolPubKey pool) topPools
+    let nm = nonMyopicStake pp s sigma t (_poolId pool) topPools
         f = maxPool pp rPot (unStakeShare nm) (unStakeShare s)
         fHat = floor (p * (fromRational . coinToRational) f)
      in memberRew (Coin fHat) pool t nm