Bug 6096 Correctly return arrayref from GetAllShelves

Bug 6096 Correctly return arrayref from GetAllShelves

Follow on from bug 5529 GetAllShelves was also vaguely stuffing
an arrayref into an array
Some signs of cut and paste (unnecessary @params variable)
Calling code now does not have to shuffle the return about
to get the reference. Also removed a debug warn

Signed-off-by: fdurand <frederic.durand@univ-lyon2.fr>
Signed-off-by: Chris Cormack <chrisc@catalyst.net.nz>
(cherry picked from commit c0655aabe47cfe21e7846b7a8956db92c1e5b5d2)

Signed-off-by: Chris Nighswonger <chris.nighswonger@gmail.com>