User without edit right cannot force edit lock

Reproduction steps:

• With two users: Admin (having edit right) and User1 (without edit rights)
• Create a page with Admin and starts an editing session
• On another browser open an editing session with User1: this edit session should use /editcr/ since the user doesn't have edit right

Expected result:

• User1 should be able to start editing the page

Obtained result:

• A warning is displayed arguing that Admin has an edition lock on the page and asking to force it
• when the user chose to force it, he's redirected to /edit/ actions for which he doesn't have rights, so a message is displayed specifying that the action is forbidden

IMO this should be fixed by not checking the lock at all in case of /editcr/ action: in such case, we don't really care if another edit session exists, since the user will produce a change request that can be rebased etc.