[dashboard] create ("plus") button fails

[Stan Lagun]

On a form that has native Horizon "plus" button and its custom murano-dashboard version to create referenced Murano component the later fails with generic error message. In dashboard log I saw

GET /murano/catalog/%5B%5B%22OpenStack%20Region%22,%20%22/murano/catalog/add/7c4a83a6c529491981603d44b0dcd942/ec976bb562ad43f3ab16cd391a274f39/False/True%22%5D%5D HTTP/1.1" 404 10614

When there is only a single version of that button on a single form everything work as expected

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/121816
Committed: https://git.openstack.org/cgit/stackforge/murano-dashboard/commit/?id=aece5d0087db1904905a85d3db2d8439953e390e
Submitter: Jenkins
Branch: master

commit aece5d0087db1904905a85d3db2d8439953e390e
Author: Timur Sufiev <email address hidden>
Date: Tue Sep 16 15:40:30 2014 +0400

    Fix for nested apps add-select widget

    The previous version of murano add-select widget didn't work in case
    there were both vanilla horizon add-select widget and custom murano
    one. Avoid this by wrapping parsing json inside try .. catch block to
    continue script execution in case vanilla add-select was found, also
    simplify creating custom add-select widget a bit.

    This patch relies on https://review.openstack.org/#/c/117021/6

    Co-Authored-By: Ekaterina Chernova <email address hidden>
    Closes-Bug: #1384178
    Change-Id: Ia6d895e4bbeb1238815d2c4bb57d706da9655f45