ct: return an error if we can't enter into CT
ct: return an error if we can't enter into CT

Signed-off-by: Andrey Vagin <74c05afa918858348d6db8037d82fa8124870113@openvz.org>

xemul/libct,LK4D4/libct,avagin/libct,xemul/libct,avagin/libct,hallyn/libct,xemul/libct,xemul/libct,hallyn/libct,LK4D4/libct,LK4D4/libct,avagin/libct,hallyn/libct