Bug 20100: (QA follow-up) Pref description and improve code in member-flags
Two points as mentioned on Bugzilla comment29.
[1] Improve pref description. Feedback from comment30 incorporated.
[2] Improve code in member-flags. Check if we change librarian flag first.
Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
Tested the die with "disable_superlibrarian_privs => 0" in member-flags.
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>