rpc: remove cs_main lock from `createrawtransaction`

This is a pure utility function that doesn't use
main's data structures, so it does not require that lock.

src/rpcrawtransaction.cpp

@@ -353,7 +353,6 @@ UniValue createrawtransaction(const UniValue& params, bool fHelp)
             + HelpExampleRpc("createrawtransaction", "\"[{\\\"txid\\\":\\\"myid\\\",\\\"vout\\\":0}]\", \"{\\\"data\\\":\\\"00010203\\\"}\"")
         );
 
-    LOCK(cs_main);
     RPCTypeCheck(params, boost::assign::list_of(UniValue::VARR)(UniValue::VOBJ)(UniValue::VNUM), true);
     if (params[0].isNull() || params[1].isNull())
         throw JSONRPCError(RPC_INVALID_PARAMETER, "Invalid parameter, arguments 1 and 2 must be non-null");