Merge debootstrap 1.0.112 from Debian Sid

We should merge debootstrap from Debian Sid because it has some very notable speed enhancements. Full changelog below:

debootstrap (1.0.112) unstable; urgency=low

  [ Thomas Lange ]
  * optimize code, make debootstrap faster (Closes: #871835)
    - use hash instead of grep for each line we read
    - we can use elsif, because the line can't match both patterns
    - There's no need to print the dependencies for each package separately,
      if when later do sort|uniq, so just collect all dependencies in a hash
      and print them at the end
    - do not read all lines of the Packages file into the perl scripts,
      egrep is used for filtering only the lines we need to read, since egrep
      is faster than perl, this save a lot of time
    - speed up by using grep -P and setting LC_ALL=C
    - automatic detect if grep support perl regex
    - in this part, we only need the package name and priority this makes
      another little speedup, since the perl part need less lines to parse

 -- Hideki Yamane <email address hidden> Sun, 23 Dec 2018 18:24:00 +0900

debootstrap (1.0.111) unstable; urgency=medium

  * Team upload

  [ Simon McVittie ]
  * Disable merged /usr by default when making a buildd chroot (closes: #914208)

 -- Julien Cristau <email address hidden> Fri, 30 Nov 2018 21:01:08 +0100

debootstrap (1.0.110) unstable; urgency=medium

  [ Luca Falavigna ]
  * Add (Ubuntu) disco as a symlink to gutsy.

  [ Hideki Yamane ]
  * Add debian/source/lintian-overrides to ignore lintian warnings
    since it is really necessary for debootstrap

 -- Hideki Yamane <email address hidden> Thu, 08 Nov 2018 07:16:42 +0900

debootstrap (1.0.109) unstable; urgency=medium

  [ Raphaël Hertzog ]
  * Keep all script files in the udeb so that derivatives can use the
    udeb built by Debian. Related to #893713.

  [ Hideki Yamane ]
  * Just set Standards-Version: 4.2.1 without change

 -- Hideki Yamane <email address hidden> Mon, 10 Sep 2018 02:42:58 +0900

From what I can see, xnox's delta should be kept:

  * Demote arch-test to suggests.
  * Drop ubuntu-archive-kerying (sic) suggests, such a package does not
    exist in Ubuntu.

I'll go ahead and merge/upload but mark this bug as block-proposed to wait for xnox and/or someone else from Foundations to ack and do testing independent of mine. After reviewing the Debian changes myself they are sane, but I also don't want to step on toes and have it migrate before people get back from vac.