Beware dated Gerrit changes

[Stephan Bergmann]

In the fast-paced world of LibreOffice development, the Jenkins 
Verified+1 of a Gerrit change's latest patch set may easily have become 
irrelevant by the time the change is submitted, if there has been 
sufficient change on the relevant git branch between the patch set's 
parent and the submit date.

I have filed <https://bugs.chromium.org/p/gerrit/issues/detail?id=13239> 
"Color-code age of a patch set's parent" as a Gerrit enhancement idea 
now that might help spot such issues.

As a corollary, when creating a Gerrit change, make sure the change's 
parent is sufficiently recent to begin with.  Pull early, pull often.