CMakeLists: Drop LS2CXX and LUNA_SERVIVCE2 dependency

* there isn't any luna-service2++
* LUNA_SERVIVCE2 is probably typo and duplicated by LS2 few
  lines above

Signed-off-by: Martin Jansa <Martin.Jansa@gmail.com>
palmsystemextensio: adapt to new LS2 APIs

Signed-off-by: Martin Jansa <Martin.Jansa@gmail.com>
CMakeLists: check only for libsystemd pkg

* compat libs are now merged into libsystemd

Signed-off-by: Martin Jansa <Martin.Jansa@gmail.com>