Fix startup scripts when restarting container (#476)

`20_start-postgresql.sh` and `40_prepare_aiida.sh`  scripts were broken,
as they would fail when a container was restarted. 
 - Delete old ${PSQL_LOGFILE}.1.gz file before trying to create a new one
 - Remove stale verdi daemon pid files, which would cause the `verdi migrate` commands to fail. This is faster than `verdi daemon stop`. We suppose that the daemon is
not running when we start/restart the container.

---------

Co-authored-by: Daniel Hollas <danekhollas@gmail.com>

stack/base-with-services/before-notebook.d/20_start-postgresql.sh

@@ -22,7 +22,8 @@ else
     chmod -R g-rwxs "${PGDATA}"
 
     if [[ -f ${PGDATA}/logfile ]]; then
-         mv "${PSQL_LOGFILE}" "${PSQL_LOGFILE}.1" && gzip "${PSQL_LOGFILE}.1"
+        rm -f "${PSQL_LOGFILE}.1.gz"
+        mv "${PSQL_LOGFILE}" "${PSQL_LOGFILE}.1" && gzip "${PSQL_LOGFILE}.1"
     fi
     # Cleaning up the mess if PostgreSQL was not shutdown properly.
     rm -vf "${PGDATA}/postmaster.pid"

stack/base/before-notebook.d/40_prepare-aiida.sh

@@ -74,6 +74,9 @@ load_computer('${computer_name}').set_minimum_job_poll_interval(${job_poll_inter
 else
 
   # Migration will run for the default profile.
+  pgrep -af 'verdi.* daemon' && echo "ERROR: AiiDA daemon is already running!" && exit 1
+  ## clean up stale PID-files -> .aiida/daemon/circus-{profile-name}.pid
+  rm -f /home/${NB_USER}/.aiida/daemon/circus-*.pid
   verdi storage migrate --force
 
 fi