Handle empty depends.conf files

I forgot that when there are no dependencies, we don't generate the
depends.conf file at all.  Handle that case.
Failure of a final hook should mark the commands as failed

If a final hook fails, we have to mark the indivudual commands for
eachbuild as failed, otherwise, the final hook will not be rerun if we
rerun "efsdeploy $command".x
Abort if there are runtime dependencies on test distributions

It is VERY rare for a distribution to have runtime dependencies on the
various Test::* modules, but they are creeping into the dependencies
via poorly defined metadata.  If the project doesn't start with Test-,
or the efsdepoy rules do not have the perl5_runtime_test_depends
option, then abort, so we can fix these.

We do NOT want to have to deploy Test distros to the prod environment.
This may prove to be a lost cause, but we're not giving up yet.