Re: Tracing down buildfarm "postmaster does not shut down" failures

I wrote:
> ... However, there is something else happening
> on axolotl.  Looking at the HEAD and 9.5 branches, there are three very
> similar failures in the ECPG step within the past 60 days:
> http://buildfarm.postgresql.org/cgi-bin/show_log.pl?nm=axolotl&dt=2016-02-08%2014%3A49%3A23
> http://buildfarm.postgresql.org/cgi-bin/show_log.pl?nm=axolotl&dt=2015-12-15%2018%3A49%3A31
> http://buildfarm.postgresql.org/cgi-bin/show_log.pl?nm=axolotl&dt=2015-12-12%2001%3A44%3A39

Oh look, searching with the "failures" BF webpage turns up a fourth such
failure on sungazer:

http://buildfarm.postgresql.org/cgi-bin/show_log.pl?nm=sungazer&dt=2016-01-18%2014%3A45%3A15

The plot thickens.  I still have no clue what's going wrong though.
        regards, tom lane