Bug 13401 - sort branches alphabetically in admin/authorised_values.pl

Bug 13401 - sort branches alphabetically in admin/authorised_values.pl

This patch adds a sort of branches alphabetically by name in authorised values administration, like in many other pages.

Also replaces var $branch (too ambigus) by $branchcode.

Test plan :
- Create 2 branches : code=AAA,name=Zbranch and code=ZZZ,name=Abranch
- Create a new authorized value : admin/authorised_values.pl
- Look at "Libraries limitation" :
=> Without patch branches are sorted by code : Zbranch then Abranch
=> Without patch branches are sorted by name : Abranch then Zbranch
- Select a branch and save
- Re-edit
=> Check the same branch is selected

Followed test plan. Patch behaves as expected.
Signed-off-by: Marc Veron <veron@veron.ch>
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>
Signed-off-by: Mason James <mtj@kohaaloha.com>