torcontrol: Add missing copyright header

src/torcontrol.cpp

@@ -1,3 +1,8 @@
+// Copyright (c) 2015-2017 The Bitcoin Core developers
+// Copyright (c) 2017 The Zcash developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
 #include "torcontrol.h"
 #include "utilstrencodings.h"
 #include "net.h"