Re: odd buildfarm failure - "pg_ctl: control file appears to be corrupt"

I pushed the retry-loop-in-frontend-executables patch and the
missing-locking-in-SQL-functions patch yesterday.  That leaves the
backup ones, which I've rebased and attached, no change.  It sounds
like we need some more healthy debate about that backup label idea
that would mean we don't need these (two birds with one stone), so
I'll just leave these here to keep the cfbot happy in the meantime.