Bug#903865: reportbug: should automatically add the ftbfs tag for the does-not-build severity

[Vincent Lefevre <vincent@vinc17.net>]

Package: reportbug
Version: 7.5.0
Severity: wishlist

A new tag "ftbfs" has recently been added:

  https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=898481

When one selects the "does-not-build" virtual severity

5 does-not-build  a bug that stops the package from being built from source.
                  (This is a 'virtual severity'.)

reportbug should automatically add this ftbfs tag to the bug,
since this is exactly what this virtual severity is about.

-- Package-specific info:
** Environment settings:
EDITOR="/home/vinc17/bin/eclient"
PAGER="less -Lis"
VISUAL="/home/vinc17/bin/eclient"
EMAIL="vincent@vinc17.net"
INTERFACE="text"

** /home/vinc17/.reportbugrc:
reportbug_version "2.10"
mode advanced
ui text
realname "Vincent Lefevre"
email "vincent@vinc17.net"
mua mutt
cc

-- System Information:
Debian Release: buster/sid
  APT prefers unstable-debug
  APT policy: (500, 'unstable-debug'), (500, 'stable-updates'), (500, 'unstable'), (500, 'testing'), (500, 'stable'), (1, 'experimental')
Architecture: amd64 (x86_64)

Kernel: Linux 4.16.0-2-amd64 (SMP w/8 CPU cores)
Locale: LANG=POSIX, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8), LANGUAGE=POSIX (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)
LSM: AppArmor: enabled

Versions of packages reportbug depends on:
ii  apt                1.6.3
ii  python3            3.6.6-1
ii  python3-reportbug  7.5.0
ii  sensible-utils     0.0.12

reportbug recommends no packages.

Versions of packages reportbug suggests:
pn  claws-mail                      <none>
pn  debconf-utils                   <none>
ii  debsums                         2.2.3
ii  dlocate                         1.07+nmu1
ii  emacs25-bin-common              25.2+1-6+b3
ii  file                            1:5.33-3
ii  gnupg                           2.2.8-3
ii  postfix [mail-transport-agent]  3.3.0-1+b1
pn  python3-urwid                   <none>
pn  reportbug-gtk                   <none>
ii  xdg-utils                       1.1.3-1

Versions of packages python3-reportbug depends on:
ii  apt                1.6.3
ii  file               1:5.33-3
ii  python3            3.6.6-1
ii  python3-apt        1.6.2
ii  python3-debian     0.1.32
ii  python3-debianbts  2.7.2
ii  python3-requests   2.18.4-2

python3-reportbug suggests no packages.

-- no debconf information