removed escape sequence not tolerated by LuaJIT (249b)

"It would appear LuaJIT is simply being stricter about escape sequences in strings." -- http://lua-users.org/lists/lua-l/2011-09/msg00267.html

Escaping the left bracket at language.lua:65 is tolerated by build 248 and not tolerated by build 249b, which uses LuaJIT. The following stacktrace occurs in 249b:

[Server] Script Error #1: lua/base/language.lua:65: invalid escape
sequence near '""%s":       '
Call stack:
#1: originalScriptLoad lua/EventTester.lua:191
fileName = "lua/base/language.lua"
reload = nil
#2: Load lua/base/eventhooks.lua:164
file = "lua/base/language.lua"
#3: lua/base/server.lua:38
Scripts =  {10="lua/base/settings.lua", 11="lua/base/eventhooks.lua",
12="lua/base/serveradmincommands.lua", 13="lua/base/language.lua",
14="lua/base/pluginloader.lua", 1="lua/dkjson.lua",
2="lua/base/class.lua", 3="lua/base/globals.lua",
4="lua/base/eventfunctions.lua", 5="lua/base/menufunctions.lua",
6="lua/base/playerfunctions.lua", 7="lua/base/configfileutility.lua",
8="lua/base/serveradmin.lua", 9="lua/base/config.lua" }
(for generator) = function
(for state) =  {10="lua/base/settings.lua",
11="lua/base/eventhooks.lua", 12="lua/base/serveradmincommands.lua",
13="lua/base/language.lua", 14="lua/base/pluginloader.lua",
1="lua/dkjson.lua", 2="lua/base/class.lua", 3="lua/base/globals.lua",
4="lua/base/eventfunctions.lua", 5="lua/base/menufunctions.lua",
6="lua/base/playerfunctions.lua", 7="lua/base/configfileutility.lua",
8="lua/base/serveradmin.lua", 9="lua/base/config.lua" }
(for control) = nan
i = 13
script = "lua/base/language.lua"
#4: scriptLoad [C]:-1
#5: Load lua/EventTester.lua:191
fileName = "lua/base/server.lua"
reload = nil