Results should be invalidated on settings changes

[Michał Sawicz]

Whenever you change a setting, results of a scope should be marked invalid, so that when you go back from the setting pane the results refresh.

Steps to reproduce (soon, now in silo):
* go to music scope settings
* disable 7digital
* go back

Expected
* no more 7digital results in music

Current
* 7digital results still there until you start searching

ProblemType: Bug
DistroRelease: Ubuntu 14.10
Package: unity-plugin-scopes 0.5.4+14.10.20140826-0ubuntu1
ProcVersionSignature: Ubuntu 3.16.0-10.15-generic 3.16.1
Uname: Linux 3.16.0-10-generic x86_64
NonfreeKernelModules: nvidia wl
ApportVersion: 2.14.6-0ubuntu2
Architecture: amd64
CurrentDesktop: Unity
Date: Wed Aug 27 10:47:15 2014
SourcePackage: unity-scopes-shell
SystemImageInfo: Error: [Errno 2] Nie ma takiego pliku ani katalogu: 'system-image-cli'
UpgradeStatus: No upgrade log present (probably fresh install)

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Michi Henning (michihenning)]

Doesn't affect scopes-api because it never touches the settings database. The shell writes it, and scopes read it.