Mark EnginioClientConnection::serviceUrl as public

The function should be public as the Enginio allows usage of different
backend urls.

Change-Id: I9a665de26137f4641618f40044b182a21aaf670f
Reviewed-by: Frederik Gladhorn <frederik.gladhorn@digia.com>
Merge remote-tracking branch 'origin/release' into stable

Change-Id: I4b9ced111eae96d6064be237d80e5038888100dd
Merge "Merge remote-tracking branch 'origin/release' into stable" into refs/staging/stable