guide:fixed the problem of creating richdir

tower:https://tower.im/projects/8a6342c556be4c4eb898fdd7fd6fcb2f/todos/8c54b536f34e4f998013c88e21ae0713/

problem:
1.when the user connect muti-sreen and finished the step of creating richdir , but the guide could not jump to next step.
2.when the user just move one desktop file over another desktop file without create richdir some times, and the guide will jump to next step.

solve method:
1.change the 'RichDirUpdate' dbus signal to 'RichdirCreate'
2.use the 'RichdirCreate' signal instead of 'ItemUpdate'

Change-Id: Ie6a428b8ebc74277137b09c566f763c8154a7fd3