snapcraft prints the setup dir deprecated warning even if it's not a snapcraft dir

[Leo Arias]

We moved the snap assets from setup/gui to snap/gui. So snapcraft started printing the following deprecation warning when it finds the setup dir:

DEPRECATED: Assets in 'setup/gui' should now be placed in 'snap/gui'.
See http://snapcraft.io/docs/deprecation-notices/dn3 for more information.

However, the same warning is printed even if the setup dir doesn't contain any snapcraft assets. For example, the golem project has a setup dir in the root of the tree that has nothing to do with snapcraft, and it still gets the warning. This is confusing and ugly.

We could easily improve it a little checking for the setup/gui dir, instead of just setup. Even better if we check for the contents of setup/gui before printing the warning.

To reproduce:

$ snapcraft init
$ emacs snap/snapcraft.yaml
# replace the part with:
parts:
  my-part:
    source: .
    plugin: dump
$ mkdir setup
$ snapcraft

[Kyle Fazzari (kyrofa)]

Agreed, checking for setup/gui instead of just setup/ sounds like the right solution.