Bug#916297: reportbug: crash after using "Display modified configuration files"

[Nemo Inis <nemoinis@hotmail.com>]

Package: reportbug
Version: 7.5.1
Severity: important

Dear Maintainer,

When reporting a bug, reportbug sometimes issues a warning that "The following
configuration files have been modified:" (for the package being reported
against).
It then gives the option to Send the modified files, or "Display modified
configuration files (exit with "q")"

Clicking that button displays the pertinent configuration files OK, but after
pressing q to exit back to the bug, reportbug dies with:

TypeError: on_child_exited() takes 2 positional arguments but 3 were given




-- Package-specific info:
** Environment settings:
EDITOR="vi"
PAGER="less -iXE"
INTERFACE="gtk2"

** /home/jpd/.reportbugrc:
reportbug_version "6.2.1"
mode novice
ui gtk2
realname "Nemo Inis"
email "nemoinis@hotmail.com"
no-cc
header "X-Debbugs-CC: nemoinis@hotmail.com"
smtphost smtp.telus.net

-- System Information:
Debian Release: buster/sid
  APT prefers testing
  APT policy: (500, 'testing')
Architecture: i386 (i686)

Kernel: Linux 4.17.0-3-686-pae (SMP w/4 CPU cores)
Locale: LANG=en_US.utf8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8), LANGUAGE=en_US.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)

Versions of packages reportbug depends on:
ii  apt                1.8.0~alpha2
ii  python3            3.6.7-1
ii  python3-reportbug  7.5.1
ii  sensible-utils     0.0.12

reportbug recommends no packages.

Versions of packages reportbug suggests:
pn  claws-mail                                 <none>
pn  debconf-utils                              <none>
pn  debsums                                    <none>
pn  dlocate                                    <none>
pn  emacs24-bin-common | emacs25-bin-common    <none>
ii  exim4                                      4.91-8
ii  exim4-daemon-light [mail-transport-agent]  4.91-8+b1
ii  file                                       1:5.34-2
ii  gnupg                                      2.2.11-1
pn  python3-urwid                              <none>
pn  reportbug-gtk                              <none>
ii  xdg-utils                                  1.1.3-1

Versions of packages python3-reportbug depends on:
ii  apt                1.8.0~alpha2
ii  file               1:5.34-2
ii  python3            3.6.7-1
ii  python3-apt        1.7.0
ii  python3-debian     0.1.33
ii  python3-debianbts  2.7.2
ii  python3-requests   2.20.0-2

python3-reportbug suggests no packages.

-- no debconf information