* enumerator.c (lazy_uniq_i): create new hash for each calls.
  [Fix GH-1820]

Currently

	2.5.0-preview1 :001 > arr = (0..100).lazy.uniq{|i| i % 10}
	 => #<Enumerator::Lazy: #<Enumerator::Lazy: 0..100>:uniq>
	2.5.0-preview1 :002 > arr.to_a
	 => [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
	2.5.0-preview1 :003 > arr.to_a
	 => []

Expected

arr.to_a to always return same output

From: Anmol Chopra <anmolchopra@rocketbox.in>

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@62731 b2dd03c8-39d4-4d8f-98ff-823fe69b080e