Enable the "limit" param in /api/search

Conflicts:
	CHANGELOG.md

Commit adds a check whether Organization exists before User is added to
the organization.

Fixes #3151.

restart grafana after upgrade

I've forgotten to update the systemctl start to restart in my first commit

The current script only tries to start the already running grafana process after an upgrade. This leads to errors due to changed js and css hashes while grafana is delivering the old ones. To load the new sources we need to restart grafana after an upgrade.