test: fix hanging http obstext test

Set the Connection header to 'close' to work around a v0.10 quirk.
Prevents the test from timing out due to a still open TCP connection.
Test introduced in 1e45a61 ("deps: update http-parser to version 1.2").

PR-URL: #5511
Reviewed-By: James M Snell <jasnell@gmail.com>

test/simple/test-http-header-obstext.js

@@ -8,9 +8,9 @@ var server = http.createServer(common.mustCall(function(req, res) {
 server.listen(common.PORT, function() {
   http.get({
     port: common.PORT,
-    headers: {'Test': 'Düsseldorf'}
+    headers: {'Connection': 'close', 'Test': 'Düsseldorf'}
   }, common.mustCall(function(res) {
     assert.equal(res.statusCode, 200);
     server.close();
   }));
-});
+});