It is helpful to have timestamps on the ping failures so that they
can be matched against the bitbake logs. It is also useful to understand
how long the server takes for form a reply verses when it is sent.
(Bitbake rev: 65969a7a8f5ae22c230431d2db080eb187a27708)
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>