Code style fix.

This if statement is a little obtuse and using braces here
improves readability.

src/script/interpreter.cpp

@@ -1227,8 +1227,9 @@ bool TransactionSignatureChecker::CheckSequence(const CScriptNum& nSequence) con
     if (!(
         (txToSequenceMasked <  CTxIn::SEQUENCE_LOCKTIME_TYPE_FLAG && nSequenceMasked <  CTxIn::SEQUENCE_LOCKTIME_TYPE_FLAG) ||
         (txToSequenceMasked >= CTxIn::SEQUENCE_LOCKTIME_TYPE_FLAG && nSequenceMasked >= CTxIn::SEQUENCE_LOCKTIME_TYPE_FLAG)
-    ))
+    )) {
         return false;
+    }
 
     // Now that we know we're comparing apples-to-apples, the
     // comparison is a simple numeric one.