Jenkins verification of gerrit patches

As you may have noticed, Jenkins is now setting 'Verify +1' on patches
it built successfully.
It does not set -1 yet, as the failure mode are still unreliable at times...
It start putting V+1 because now Jenkins do build on all 3 main
platforms (at first it was building only Mac, then Mac and Windows..
now it build Mac, Windows and Linux)

If the verification failed on one or more platform, and you feel that
is not related to our patch, try re-basing the patch, hopefully the
underlying cause would have disappeared in the interval.

A build verification across all 3 platforms takes about 90 minutes...
but at time there are a queue...
so the time between upload of a patch and the verification result can
be few hours...
(the real execution time vary a lot depending on how much ccache can
do to help and which specific slave got the build... Mac slace are all
identical, but Windows slaves vary noticably in perf.)

FYI: the build are 'default build'. autogen.config contains pretty
much nothing beyond
--with-external-tar, --wtih-ant-home and sometimes --disable-dependency-tracking



Norbert.