Define OmniCC only if its not already defined (needed for me running OmniCC + tullaCC at the same time)

diff --git a/tullaCC/cc.lua b/tullaCC/cc.lua
index 790fabb..40c1777 100644
--- a/tullaCC/cc.lua
+++ b/tullaCC/cc.lua
@@ -7,7 +7,7 @@
 --]]

 --constants!
-OmniCC = true --hack to work around detection from other addons for OmniCC
+OmniCC = OmniCC or true --hack to work around detection from other addons for OmniCC
 local ICON_SIZE = 36 --the normal size for an icon (don't change this)
 local FONT_FACE = STANDARD_TEXT_FONT --what font to use
 local FONT_SIZE = 18 --the base font size to use at a scale of 1