Sphinx 2.0 no longer works on python 2.7, so we need to start capping
it there as well.
The errors are as follow:
Requirement(package='sphinx', location='', specifiers='!=1.6.6,!=1.6.7,>=1.6.5'
does not match "python_version>='3.4'"
Requirement(package='sphinx', location='', specifiers='!=1.6.6,!=1.6.7,>=1.6.5'
does not match "python_version=='2.7'"
Could not find a global requirements entry to match package sphinx. If the package
is already included in the global list, the name or platform markers there may not
match the local settings.
Change-Id: I6dad56ffbb9e85e36cacea1a89565c2fc8248fbf
15c842fba2