Use double underscore to avoid tainting blizzard

diff --git a/oUF_Experience.lua b/oUF_Experience.lua
index 7f68c70..74b3ff2 100644
--- a/oUF_Experience.lua
+++ b/oUF_Experience.lua
@@ -1,4 +1,4 @@
-local _, ns = ...
+local __, ns = ...
 local oUF = ns.oUF or oUF
 assert(oUF, 'oUF Experience was unable to locate oUF install')