Fix broken pg_dump command

Error in the backup command found by Sam on the forums.
See http://www.openmicroscopy.org/community/viewtopic.php?f=5&t=6852
Remove '#sh' from script
merge develop -D org -I include -E exclude: PR 450 (omero: Python 2.6 is the minimum supported version)
merge develop -D org -I include -E exclude: PR 509 (Fix broken pg_dump command (rebased onto develop))