Correctly report high-S violations

src/script/interpreter.cpp

@@ -165,7 +165,10 @@ bool static IsLowDERSignature(const valtype &vchSig, ScriptError* serror) {
         return set_error(serror, SCRIPT_ERR_SIG_DER);
     }
     std::vector<unsigned char> vchSigCopy(vchSig.begin(), vchSig.begin() + vchSig.size() - 1);
-    return CPubKey::CheckLowS(vchSigCopy);
+    if (!CPubKey::CheckLowS(vchSigCopy)) {
+        return set_error(serror, SCRIPT_ERR_SIG_HIGH_S);
+    }
+    return true;
 }
 
 bool static IsDefinedHashtypeSignature(const valtype &vchSig) {