Fix a bad global in poller's FFI code.

src/poller.nobj.lua

@@ -303,6 +303,7 @@ void poller_remove_item(ZMQ_Poller *poller, int idx);
 		ffi_source[[
 	local fd = 0
 	local sock_type = type(${sock})
+	local sock
 	if sock_type == 'cdata' then
 		sock = obj_type_ZMQ_Socket_check(${sock})
 	elseif sock_type == 'number' then
@@ -355,6 +356,7 @@ void poller_remove_item(ZMQ_Poller *poller, int idx);
 		ffi_source[[
 	local fd = 0
 	local sock_type = type(${sock})
+	local sock
 	if sock_type == 'cdata' then
 		sock = obj_type_ZMQ_Socket_check(${sock})
 		-- find sock in items list.
@@ -404,6 +406,7 @@ void poller_remove_item(ZMQ_Poller *poller, int idx);
 		ffi_source[[
 	local fd = 0
 	local sock_type = type(${sock})
+	local sock
 	if sock_type == 'cdata' then
 		sock = obj_type_ZMQ_Socket_check(${sock})
 		-- find sock in items list.

src/pre_generated-zmq.nobj.c

@@ -3588,6 +3588,7 @@ static const char *zmq_ffi_lua_code[] = { "local ffi=require\"ffi\"\n"
 "  local idx1 = 0\n"
 "	local fd = 0\n"
 "	local sock_type = type(sock2)\n"
+"	local sock\n"
 "	if sock_type == 'cdata' then\n"
 "		sock = obj_type_ZMQ_Socket_check(sock2)\n"
 "	elseif sock_type == 'number' then\n"
@@ -3611,6 +3612,7 @@ static const char *zmq_ffi_lua_code[] = { "local ffi=require\"ffi\"\n"
 "  local idx1 = 0\n"
 "	local fd = 0\n"
 "	local sock_type = type(sock2)\n"
+"	local sock\n"
 "	if sock_type == 'cdata' then\n"
 "		sock = obj_type_ZMQ_Socket_check(sock2)\n"
 "		-- find sock in items list.\n"
@@ -3640,6 +3642,7 @@ static const char *zmq_ffi_lua_code[] = { "local ffi=require\"ffi\"\n"
 "  local idx1 = 0\n"
 "	local fd = 0\n"
 "	local sock_type = type(sock2)\n"
+"	local sock\n"
 "	if sock_type == 'cdata' then\n"
 "		sock = obj_type_ZMQ_Socket_check(sock2)\n"
 "		-- find sock in items list.\n"