Bug 11214: improve create/edit routing list links in serial collection page

Bug 11214: improve create/edit routing list links in serial collection page

When a subscription has no routing list yet, the page
serials/subscription-detail.pl shows in left menu : "Create routing list".
In serials/serials-collection.pl page, the link in table is always
"Edit routing list", even when there is no routing list.

This patch adds a conditionnal link "Edit routing list"/"Create routing
list" into serials/serials-collection.pl page.

Test plan :
- Create a subscription no. 1 without routing list and a subscription
  no. 2 with a routing list
- Go to serials/serials-collection.pl of subscription no. 1
=> You see "Create routing list" link
- Click on link
=> You see "Create routing list for"
- Go to serials/serials-collection.pl of subscription no. 2
=> You see "Edit routing list" link
- Click on link
=> You see "Edit routing list for ..."

Signed-off-by: Liz Rea <liz@catalyst.net.nz>
Functional and automated tests pass. Passes koha-qa.pl.

Signed-off-by: Katrin Fischer <Katrin.Fischer.83@web.de>
Passes all tests and QA script.
With the patch applied the serial collection page shows the
right link depending on the existance of a routing list.

Signed-off-by: Galen Charlton <gmc@esilibrary.com>
(cherry picked from commit 0c631934de5adf5c8d9d35aaaf94a19134f4a166)
Signed-off-by: Fridolin SOMERS <fridolin.somers@biblibre.com>