fdo#51819: autorecovery: fix saving password in protected documents.

Thanks to sayt@mailinator.com for the idea.

(cherry picked from commit ef87ff6680f79362a431db6e7ef2f40cfc576219)

Conflicts:
	framework/source/services/autorecovery.cxx

Change-Id: Ib79abafe3d4d3ba21f7914aeb284d86ce662824c
Reviewed-on: https://gerrit.libreoffice.org/8681
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>