timeout.rb: suppress a warning

* lib/timeout.rb (Timeout): get rid of an argument prefix warning.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@51236 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

lib/timeout.rb

@@ -48,7 +48,7 @@ module Timeout
   # :stopdoc:
   THIS_FILE = /\A#{Regexp.quote(__FILE__)}:/o
   CALLER_OFFSET = ((c = caller[0]) && THIS_FILE =~ c) ? 1 : 0
-  private_constant *%I[THIS_FILE CALLER_OFFSET]
+  private_constant :THIS_FILE, :CALLER_OFFSET
   # :startdoc:
 
   # Perform an operation in a block, raising an error if it takes longer than