FIX: exit upon failure to run the PostgreSQL 15 update

Exit code 77 is unnecessary for this update.

Prior PG updates needed a second rebuild due to several legacy issues
that have since been fixed.

We now only require a single rebuild if the PG update succeeds.

Author: mwaniki-wairungu

templates/postgres.15.template.yml

@@ -71,8 +71,9 @@ run:
           chown -R postgres:postgres /shared/postgres_data
           chown -R postgres:postgres /var/run/postgresql
         elif [ -f /root/upgrade_postgres ]; then
-          /root/upgrade_postgres
-          rm /root/upgrade_postgres
+          unset RETCODE
+          /root/upgrade_postgres || RETCODE=$?
+          [ ! $RETCODE ] && rm /root/upgrade_postgres || exit $RETCODE
         fi
         # Necessary to enable backups
         install -d -m 0755 -o postgres -g postgres /shared/postgres_backup
@@ -137,8 +138,6 @@ run:
          echo
          echo Old ${PG_MAJOR_OLD} database is stored at /shared/postgres_data_old
          echo -------------------------------------------------------------------------------------
-         # Magic exit status to denote no failure
-         exit 77
        fi
 
   - replace:

templates/postgres.template.yml

@@ -71,8 +71,9 @@ run:
           chown -R postgres:postgres /shared/postgres_data
           chown -R postgres:postgres /var/run/postgresql
         elif [ -f /root/upgrade_postgres ]; then
-          /root/upgrade_postgres
-          rm /root/upgrade_postgres
+          unset RETCODE
+          /root/upgrade_postgres || RETCODE=$?
+          [ ! $RETCODE ] && rm /root/upgrade_postgres || exit $RETCODE
         fi
         # Necessary to enable backups
         install -d -m 0755 -o postgres -g postgres /shared/postgres_backup
@@ -137,8 +138,6 @@ run:
          echo
          echo Old ${PG_MAJOR_OLD} database is stored at /shared/postgres_data_old
          echo -------------------------------------------------------------------------------------
-         # Magic exit status to denote no failure
-         exit 77
        fi
 
   - replace: