user-accounts: Fix password dialog hangs

On Fedora 31, the "Current Password: " prompt is printed by passwd, when I enter my current password wrongly. It is not clear to me why and I don't know how to debug the PAM stack, but it causes that the checkmark for the old password field is not reliable and what is worse it causes the dialog hangs when it is submitted. Let's add check for the "urrent" keyword to fix this issue.

Fixes: #766 (closed)

(cherry picked from commit 65d3b71d)