Merge #2166: [BUG] Flush the chainstate after pruning invalid entries.

0b56001 [BUG] Flush the chainstate after pruning invalid entries. (random-zebra)

Pull request description:

  Fix an edge case where the 'M' key is removed from the blockTree DB but the chainstate still contains the invalid entries, due to it not being flushed after the update.

ACKs for top commit:
  furszy:
    utACK 0b56001
  Fuzzbawls:
    utACK 0b56001

Tree-SHA512: ecd4285f3ea90ce7671e1e0978f8bfdfe34d6d135d74f9bb7161d061789b600509207e44cfe3ef7f1f41b7c905f2a429ef5e656c69f52d7719041038bb357130

src/init.cpp

@@ -1628,6 +1628,11 @@ bool AppInitMain()
                     if (fZerocoinActive && pblocktree->Read('M', nDummySupply)) {
                         LogPrintf("Pruning zerocoin mints / invalid outs, at height %d\n", chainHeight);
                         pcoinsTip->PruneInvalidEntries();
+                        if (!pcoinsTip->Flush()) {
+                            strLoadError = _("System error while flushing the chainstate after pruning invalid entries. Possible corrupt database.");
+                            break;
+                        }
+                        MoneySupply.Update(pcoinsTip->GetTotalAmount(), chainHeight);
                         pblocktree->Erase('M');
                     }
                 }