Remove deprecated method File.exists?

Author: patricklinpl

spec/tags/core/file/exist_tags.txt

@@ -1149,7 +1149,6 @@ def self.sticky?(path)
   class << self
     alias_method :delete,   :unlink
     alias_method :empty?,   :zero?
-    alias_method :exists?,  :exist?
     alias_method :fnmatch?, :fnmatch
   end