Cannot connect to ubuntu-app-platform package on consecutive installs

[Larry Price]

When trying to create a snap for an application utilizing the ubuntu-app-platform, the connection is broken on consecutive installs. This can be reproduced with the ubuntu-app-platform example from the official blog post (https://insights.ubuntu.com/2016/11/17/how-to-create-snap-packages-on-qt-applications/):

    $ sudo snap install --devmode uitk-gallery_0.3_amd64.snap
    uitk-gallery 0.3 installed
    $ uitk-gallery
    # works fine
    $ sudo snap install --devmode uitk-gallery_0.3_amd64.snap
    uitk-gallery 0.3 installed
    $ uitk-gallery
    You need to connect the ubuntu-app-platform package with your application
    to reuse shared assets, please run:
    snap install ubuntu-app-platform
    snap connect uitk-gallery:platform ubuntu-app-platform:platform

If I try to disconnect the old snap before installing again, it still doesn't work. Running the `discard-ns` command before install fixes the issue for uitk-gallery, but not for a snap which has namespaced commands (uitk-gallery.command2). The only things I've been able to use to fix this were reinstalling the (large and time-consuming) ubuntu-app-platform snap or rebooting.

zesty
snapd 2.20.1+17.04ubuntu2
ubuntu-app-platform 1