Stop building witnesses if shutdown requested, fixes #330

src/wallet/wallet.cpp

@@ -1146,6 +1146,9 @@ void CWallet::BuildWitnessCache(const CBlockIndex* pindex, bool witnessOnly)
     LogPrintf("%s: height=%d, startHeight=%d\n", __func__, height, startHeight);
 
   while (pblockindex) {
+    if (ShutdownRequested()) {
+        break;
+    }
 
     if (pblockindex->GetHeight() % 100 == 0 && pblockindex->GetHeight() < height - 5) {
       LogPrintf("Building Witnesses for block %i %.4f complete, %d remaining\n", pblockindex->GetHeight(), pblockindex->GetHeight() / double(height), height - pblockindex->GetHeight() );