Author: Paul Holden
MDL-69448 backup: fix capability checks when unable to copy user data.
When a given user doesn't have the capability to "Include user data"
during course copying, freeze the form element rather than not adding
it at all.
This caused problems as the element was required before preceding with
the course copy.
http://git.moodle.org/gw?p=moodle.git;a=commit;h=4ff5d5ef173456fc6336f31f1e6c01d8628a911d
http://github.com/moodle/moodle/commit/4ff5d5ef173456fc6336f31f1e6c01d8628a911d
+ 3.9 en [copyfieldnotfound,core_backup]