Thank You All for responses
It seems, that the problem is somewhere in systemd.
Ech, nothing changed
But - to avoid broken deps i've typed:
yum downgrade systemd libgudev1 systemd-python systemd-libs systemd-python3
Systemd was downgraded from 208-16.fc20.x86_64 to 208-9.fc20.x86_64 and it seems that everything is OK now - laptop is powered off in a few seconds again.
First serious problem with Fedora in last years
I think that the next step to solve the problem will be to submit new bug on bugzilla. It's nothing serious after all but it can be frustrating on every shutdown.