D6003: Tell user to unlock his session only

[Yury Kudryashov]

urkud added a reviewer: Plasma.

REPOSITORY
  R133 KScreenLocker

REVISION DETAIL
  https://phabricator.kde.org/D6003

To: urkud, #plasma
Cc: plasma-devel, ZrenBot, spstarr, progwolff, lesliezhai, ali-mohamed, 
jensreuterberg, abetts, sebas, apol, mart, lukas