Release 4.17 of the PostgreSQL Buildfarm client

I have just cut release 4.17 of the PostgreSQL Buildfarm client. It is
available at <http://www.pgbuildfarm.org/downloads/latest-client.tgz>.

Changes of note:

* use PGCTLTIMEOUT instead of hardcoded timeout settings
* shipped config file is renamed to build-farm.conf.sample to avoid
overwriting a default config file
* use configured make command in make_bin_installcheck
* restrict restart sleeps to Windows platforms
* fix trigger_exclude pattern in build-farm.conf
* protect git checkout with a lock if using git_use_workdirs

For the most part, the thing of significance it the PGCTLTIMEOUT change,
which follows up on some changes in core code. The new code defaults
this setting to 120, but it can be set in the config file. If you don't
need any of the other changes (most people probably won't) then just
adding something like

PGCTLTIMEOUT => '120',

to the build_env stanza of your config file should do the trick, and you
can happily wait for the next release.

cheers

andrew