Bug 10419: (followup) - tidy up cronjob for deleting patrons

Bug 10419: (followup) - tidy up cronjob for deleting patrons

This followup adds:
- execute flag (+x) for the cronjob script.
- replaces --dry-run with --confirm (according with existing scripts).
- changes output text (remove 'first person' style).
- updates the doc and simplifies the dates parameters.
- changes flags PrintError and RaiseError for the dbh in order to catch
  something if an error occurs...

Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>
Signed-off-by: Chris Cormack <chrisc@catalyst.net.nz>
Signed-off-by: Galen Charlton <gmc@esilibrary.com>
Signed-off-by: Katrin Fischer <Katrin.Fischer.83@web.de>
Signed-off-by: Galen Charlton <gmc@esilibrary.com>