test_http_parser: fix for URI too long errors (again)

The random garbage generator may occasionally generate URIs that
are too long and cause the URI-specific error to be raised
instead of the generic parser error we recently introduced.

Follow-up-to: commit 742c4d7

test/unit/test_http_parser.rb

@@ -761,7 +761,7 @@ def test_horrible_queries
     get = "GET /#{rand_data(10,120)} HTTP/1.1\r\n"
     get << "X-Test: test\r\n" * (80 * 1024)
     parser.buf << get
-    assert_raises Unicorn::HttpParserError do
+    assert_raises(Unicorn::HttpParserError,Unicorn::RequestURITooLongError) do
       parser.parse
     end
     parser.clear