Fix recv() method in FFI bindings.

src/pre_generated-zmq.nobj.c

@@ -2087,7 +2087,7 @@ static const char zmq_ffi_lua_code[] = "local ffi=require\"ffi\"\n"
 "	end\n"
 "\n"
 "	-- receive message\n"
-"	err2 = zmq_recvmsg(self, msg, flags2)\n"
+"	err2 = C.zmq_recvmsg(self, msg, flags2)\n"
 "	if err2 >= 0 then\n"
 "		local data = ffi.string(C.zmq_msg_data(msg), C.zmq_msg_size(msg))\n"
 "		-- close message\n"

src/socket.nobj.lua

@@ -723,7 +723,7 @@ local tmp_msg = ffi.new('zmq_msg_t')
 	end
 
 	-- receive message
-	${err} = zmq_recvmsg(${this}, msg, ${flags})
+	${err} = C.zmq_recvmsg(${this}, msg, ${flags})
 	if ${err} >= 0 then
 		local data = ffi.string(C.zmq_msg_data(msg), C.zmq_msg_size(msg))
 		-- close message