Bug 29826: Manage call of Template Plugin Branches GetName() with null or empty branc...

Bug 29826: Manage call of Template Plugin Branches GetName() with null or empty branchcode

Bug 26587 added a concatenation that sends a warning if var is undef :
$ prove t/db_dependent/Template/Plugin/Branches.t
Use of uninitialized value $branchcode in concatenation (.) or string at /kohadevbox/koha/Koha/Template/Plugin/Branches.pm line 35.

This patch adds an early return empty string when GetName is called with $branchcode null or empty string.

Test plan :
1) Run t/db_dependent/Template/Plugin/Branches.t without patch
2) Run with the patch to see warning disappear

Signed-off-by: David Nind <david@davidnind.com>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
Signed-off-by: Fridolin Somers <fridolin.somers@biblibre.com>