Correct a test to use true/false instead of 1/0.

t/hash/exists.t

@@ -6,25 +6,25 @@ plan 8
 a = {"foo" => "bar", "baz" => "quux", "frotz" => nil}
 
 b = a.has_key?("foo")
-is b, 1, "has_key? true"
+is b, true, "has_key? true"
 
 b = a.has_key?("nope")
-is b, 0, "has_key? false"
+is b, false, "has_key? false"
 
 b = a.include?("foo")
-is b, 1, "include?"
+is b, true, "include?"
 
 b = a.key?("foo")
-is b, 1, "key?"
+is b, true, "key?"
 
 b = a.member?("foo")
-is b, 1, "member?"
+is b, true, "member?"
 
 b = a.has_value?("baz")
-is b, 1, "has_value? true"
+is b, true, "has_value? true"
 
 b = a.has_value?("frotz")
-is b, 0, "has_value? false"
+is b, false, "has_value? false"
 
 b = a.value?("foo")
-is b, 1, "value?"
+is b, true, "value?"