lalinference_pipe_utils.py: minor python3 fix
This patch resolves all of the errors encountered in dag-setup phase with ignore-gracedb-psd=False and python3.
Maintenance will be performed on git.ligo.org, containers.ligo.org, and docs.ligo.org on Tuesday 30 April 2024 starting at approximately 9am PDT. It is expected to take around twenty minutes and there will be several periods of downtime throughout the maintenance. Please address any comments, concerns, or questions to the helpdesk.
This patch resolves all of the errors encountered in dag-setup phase with ignore-gracedb-psd=False and python3.