Pin Sphinx to <1.2
Pin Sphinx to <1.2

1.2 was just released and has a bug that causes builds to fail with
the error:

  error: 'source_dir' must be a directory name (got `...doc/source`)

See: http://bugs.python.org/issue19570
and: https://bitbucket.org/birkenfeld/sphinx/pull-request/193/builddoc-shouldnt-fail-on-unicode-paths/diff

Change-Id: I56988f93a1d200185fb1564619ee57a2500ee237
Ref: https://review.openstack.org/#/c/61164

Solinea/stackalytics,mgkwill/spectrometer,zxiiro/spectrometer,0xf2/stackalytics,mhharsh/stackalytics,AlexanderYAPPO/stackalytics,mohitsethi/stackalytics,kevinbenton/stackalytics,dliu2015/stackalytics_zanata,danielmellado/stackalytics,nihilifer/stackalytics,dave-tucker/spectrometer,mgkwill/spectrometer,openstack/stackalytics,mgkwill/spectrometer,dliu2015/stackalytics_zanata,nihilifer/stackalytics,openstack/stackalytics,danielmellado/stackalytics,dliu2015/stackalytics_zanata,mgkwill/spectrometer,nihilifer/stackalytics,AlexanderYAPPO/stackalytics,Mirantis/stackalytics,stackforge/stackalytics,0xf2/stackalytics,openstack/stackalytics,zxiiro/spectrometer,Code-Fly/stackalytics,stackforge/stackalytics,0xf2/stackalytics,Solinea/stackalytics,danielmellado/stackalytics,Code-Fly/stackalytics,openstack/stackalytics,AlexanderYAPPO/stackalytics,dave-tucker/spectrometer,zxiiro/spectrometer,mhharsh/stackalytics,zxiiro/spectrometer,mgkwill/spectrometer,dave-tucker/spectrometer,Mirantis/stackalytics,dave-tucker/spectrometer,stackforge/stackalytics,Mirantis/stackalytics,dave-tucker/spectrometer,zxiiro/spectrometer,Code-Fly/stackalytics,mohitsethi/stackalytics,kevinbenton/stackalytics,mhharsh/stackalytics,0xf2/stackalytics,mohitsethi/stackalytics,Solinea/stackalytics