Bug 21417: (QA follow-up) Display default EAN as such in admin display

Bug 21417: (QA follow-up) Display default EAN as such in admin display

A branch value of null is interpreted as the default
Add text 'All libraries' to this case in the display
rather than blank so that its function is clear to the
user

Signed-off-by: Pierre-Marc Thibault <pierre-marc.thibault@inLibro.com>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>
(cherry picked from commit d70daacebae50fde8449f4cec2bb4578747610fc)
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
(cherry picked from commit f0937049f376d829d6baad81c66c298e93587acf)
Signed-off-by: Fridolin Somers <fridolin.somers@biblibre.com>