Disable 0.7 protocol (was enabled by default)

The protocol is not supported anyway. Stop announcing the server for
0.7 clients.

src/engine/shared/config_variables.h

@@ -41,7 +41,7 @@ MACRO_CONFIG_INT(SvPlayerDemoRecord, sv_player_demo_record, 0, 0, 1, CFGFLAG_SER
 MACRO_CONFIG_INT(SvDemoChat, sv_demo_chat, 0, 0, 1, CFGFLAG_SERVER, "Record chat for demos")
 MACRO_CONFIG_INT(SvServerInfoPerSecond, sv_server_info_per_second, 10, 1, 1000, CFGFLAG_SERVER, "Maximum number of complete server info responses that are sent out per second")
 MACRO_CONFIG_INT(SvVanConnPerSecond, sv_van_conn_per_second, 10, 0, 10000, CFGFLAG_SERVER, "Antispoof specific ratelimit (0 for no limit)")
-MACRO_CONFIG_INT(SvSixup, sv_sixup, 1, 0, 1, CFGFLAG_SERVER, "Enable sixup connections")
+MACRO_CONFIG_INT(SvSixup, sv_sixup, 0, 0, 1, CFGFLAG_SERVER, "Enable sixup connections")
 MACRO_CONFIG_INT(SvSkillLevel, sv_skill_level, 1, SERVERINFO_LEVEL_MIN, SERVERINFO_LEVEL_MAX, CFGFLAG_SERVER, "Difficulty level for Teeworlds 0.7 (0: Casual, 1: Normal, 2: Competitive)")
 
 MACRO_CONFIG_STR(EcBindaddr, ec_bindaddr, 128, "localhost", CFGFLAG_ECON, "Address to bind the external console to. Anything but 'localhost' is dangerous")