[ruby/uri] Prevent a warning: URI::REGEXP is obsolete

(ruby/uri#138)

ruby/uri@c00726a20a

Author: mame

test/uri/test_common.rb

@@ -11,7 +11,7 @@ def teardown
   end
 
   class Foo
-    include URI::REGEXP::PATTERN
+    include URI::RFC2396_REGEXP::PATTERN
   end
 
   def test_fallback_constants