snapcraft gated prints no message when there are no gated snaps

[Leo Arias]

When I run snapcraft gated with a snap that has nothing gated, I get:

$ snapcraft gated u1test20161003
Name Approved
elopio@ubuntu-xenial:~/packaging$

It would be better to print a message saying that there are no gated revisions. Maybe even some tips about how to add some.

[Roberto Alsina (ralsina)]

celso pointed out a few issues with the current validate() code, so I can fix this at the same time.

[Roberto Alsina (ralsina)]

https://github.com/snapcore/snapcraft/pull/849 has the fix. Did not add the "hints to explain how to add validations" because you don't want me to write those... it involves requesting canonical to enable refresh-control in a snap and so on. Looks complicated.