Make TX_SCRIPTHASH clear vSolutionsRet first

Previously unlike other transaction types the TX_SCRIPTHASH would not
clear vSolutionsRet, which means that unlike other transaction types if
it was called twice in a row you would get the result of the previous
invocation as well.

Author: petertodd

src/script/standard.cpp

@@ -58,6 +58,8 @@ bool Solver(const CScript& scriptPubKey, txnouttype& typeRet, vector<vector<unsi
         mTemplates.insert(make_pair(TX_NULL_DATA, CScript() << OP_RETURN));
     }
 
+    vSolutionsRet.clear();
+
     // Shortcut for pay-to-script-hash, which are more constrained than the other types:
     // it is always OP_HASH160 20 [20 byte hash] OP_EQUAL
     if (scriptPubKey.IsPayToScriptHash())