Add "zkey" to list of key types (used by the wallet to decide

whether or not it can be recovered if it detects bad records).

src/wallet/walletdb.cpp

@@ -641,6 +641,7 @@ ReadKeyValue(CWallet* pwallet, CDataStream& ssKey, CDataStream& ssValue,
 static bool IsKeyType(string strType)
 {
     return (strType== "key" || strType == "wkey" ||
+            strType == "zkey" ||
             strType == "mkey" || strType == "ckey");
 }