gtkrc-2.0: remove password-hint

Reverted in GTK 3:

commit 3442933dd7ea6c9f411a021a19202b91cc090610
Refs: 3.9.12-80-g3442933
Author:     Matthias Clasen <mclasen@redhat.com>
AuthorDate: Sat Aug 31 00:14:58 2013 -0400
Commit:     Matthias Clasen <mclasen@redhat.com>
CommitDate: Sat Aug 31 00:16:28 2013 -0400

    Revert "Deprecate and ignore gtk-entry-password-hint-timeout"

    This reverts commit 4b5a389e88af7e7a1fa9e33294642dcfbc2832ec.

    This change caused considerable concern about accidental
    leaking of passwords, see e.g.

    https://bugzilla.gnome.org/show_bug.cgi?id=706563
    https://bugzilla.gnome.org/show_bug.cgi?id=706873
    https://bugzilla.redhat.com/show_bug.cgi?id=994237

    We may have to do something else for password entries, such
    as the windows-style 'peekabo' icon.