v2.7.1

Changed

• When creating a pack environment during the pack installation, we now pass --no-download flag
  to the virtualenv binary. This way version of pip, wheel and distutils which is enforced by
  virtualenv is used instead of downloading the latest stable versions from PyPi.

  This results in more reproducible pack virtual environments and we also ensure pip 9.0 is used (
  there are some known issues with pip 10.0).

  If for some reason you want to revert to the old behavior, you can do that by passing
  no_download=False parameter to the packs.setup_virtualenv action. #4085

Fixed

• Fix st2 pack search and POST /api/v1/packs/index/search API endpoint so it doesn't
  return internal server error when a single pack search term is provided. (bug fix) #4083