[python-pbr/f18] (14 commits) ...remove requirements.txt, require python-pip

[Pádraig Brady]

Summary of changes:

  7421937... Update to pbr-0.5.10 (*)
  056c4cc... add build requirement python-testtools (*)
  97e9a58... update to 0.5.11 (rhbz#962132) (*)
  5d3fd27... remove unneeded requirement (*)
  fdf9f19... remove setuptools_git from requirements/BR (*)
  4aa6093... finally fix build under rhel6 (*)
  eb026da... update to 0.5.14 (rhbz 971736) (*)
  37c09a1... update to 0.5.16 (*)
  45bd1a0... Update to pbr-0.5.17 (rhbz#976026) (*)
  6944a09... update to 0.5.19 (*)
  9a0991e... remove one buildrequires python-sphinx (*)
  f13711f... update to 0.5.21 (rhbz#990008) (*)
  318a0aa... pbr now requires pip (*)
  cb36574... remove requirements.txt, require python-pip (*)

(*) This commit already existed in another branch; no separate mail sent