[phobos] [D-Programming-Language/installer] cc4d45: use 7za instead of 7z

[GitHub via phobos]

  Branch: refs/heads/master
  Home:   https://github.com/D-Programming-Language/installer
  Commit: cc4d45a4cdde945ea2cd4eeb3dd05b4289f786ee
      https://github.com/D-Programming-Language/installer/commit/cc4d45a4cdde945ea2cd4eeb3dd05b4289f786ee
  Author: Martin Nowak <code at dawg.eu>
  Date:   2015-11-28 (Sat, 28 Nov 2015)

  Changed paths:
    M create_dmd_release/common.d

  Log Message:
  -----------
  use 7za instead of 7z

- compat with older p7zip package