is removed from "required" web scenario step field

create a web scenario, in the "required" field enter something like "Login name", add step, save and reopen scenario.
entity has been converted to space.

this was broken by ZBX-4506 in revision 24635

this might have affected other functionality as well - that should be verified.

trunk should be verified as well.

setting as a blocker as it breaks the web monitoring example in the virtual appliance