testing: direct port of r4146 to fix message color issue

Porting [r4146](https://code.google.com/p/modpagespeed/source/detail?r=4146) from `apache/system_test.sh` fixes this error:

```
TEST: Messages are colored in message_history
     check_from fgrep -q color:blue;
FAILed Input: <pre style="color:brown; margin:0;">[Wed, 13 Aug 2014 13:54:20 GMT] [Warning] [12497] Invalid value for PageSpeed: Warning_trigger (should be on, off, unplugged, or noscript)</pre>
<pre style="margin:0;">[Wed, 13 Aug 2014 13:54:20 GMT] [Info] [12497] Trying to serve rewritten resource in-place: http://localhost:8050/?PageSpeed=Warning_trigger</pre>
<pre style="margin:0;">[Wed, 13 Aug 2014 13:54:20 GMT] [Info] [12497] Could not rewrite resource in-place because URL is not in cache: http://localhost:8050/?PageSpeed=Warning_trigger</pre>
     failure at line 2693
in 'Messages are colored in message_history'
FAIL.
With serf fetcher setup.
```