branch source builder fails to build unsigned packages, but doesn't see the problem

I have foolishly created my .changes without signing it and submitted it to the airline for processing. Looking at the bsb logs I see:
INFO:__main__:The PPA is: ppa:pwlars/ci-pool-001
INFO:root:Upload to the ppa: ppa:pwlars/ci-pool-001
INFO:root:Retrieving source file: bash_4.2-5ubuntu4~plars_source.changes
INFO:root:Retrieving source file: bash_4.2-5ubuntu4~plars.diff.gz
INFO:root:Retrieving source file: bash_4.2-5ubuntu4~plars.dsc
$USER not set, will use login information.
Checking signature on .changes
gpg: fatal: can't create directory `/nonexistent/.gnupg': No such file or directory
secmem usage: 0/0 bytes in 0/0 blocks of pool 0/32768
Error in finding signature verification status.
Checking signature on .dsc
Checking signature on .dsc
gpg: fatal: can't create directory `/nonexistent/.gnupg': No such file or directory
secmem usage: 0/0 bytes in 0/0 blocks of pool 0/32768
Error in finding signature verification status.
Uploading to ppa (via ftp to ppa.launchpad.net):
  Uploading bash_4.2-5ubuntu4~plars.dsc: done.
  Uploading bash_4.2-5ubuntu4~plars.diff.gz: done.
  Uploading bash_4.2-5ubuntu4~plars_source.changes: done.
Successfully uploaded packages.

Somehow, I think we need to have it check that it's signed, or apparently it will just get ignored in the ppa.