remove oslosphinx from test-requirements
remove oslosphinx from test-requirements

Horizon uses the openstackdocstheme and doesn't need oslosphinx.

Change-Id: I2cb1f0d03d5eab7b5288801877383bbf0aed93a6
Signed-off-by: Doug Hellmann <0798ebecfb7bc4dfb9d0445c2fa030eb64e1fa1c@doughellmann.com>

openstack/horizon,noironetworks/horizon,NeCTAR-RC/horizon,BiznetGIO/horizon,yeming233/horizon,noironetworks/horizon,NeCTAR-RC/horizon,noironetworks/horizon,yeming233/horizon,openstack/horizon,ChameleonCloud/horizon,yeming233/horizon,NeCTAR-RC/horizon,BiznetGIO/horizon,BiznetGIO/horizon,ChameleonCloud/horizon,BiznetGIO/horizon,ChameleonCloud/horizon,noironetworks/horizon,ChameleonCloud/horizon,openstack/horizon,yeming233/horizon,openstack/horizon,NeCTAR-RC/horizon