Error on building docs with Sphinx & python3

[Illedran]

Expected behavior and actual behavior

CMake should build the docs regardless of the python version. It currently fails when the python version is >=3.0.

Steps to reproduce the problem

cd build/
cmake -DWITH_DOC=ON ..
make doc

Proposed Fix

The error happens at this line:
https://github.com/pgRouting/pgrouting/blob/master/cmake/FindSphinx.cmake#L55
it can be fixed by modifying the python statement to

from __future__ import print_function; import sphinx; print(sphinx.__version__)

[cvvergara]

didnt have time in 2.3

[cvvergara]

Leaving this issue for later

[cvvergara]

Right now it is done with python >=3
Closing issue.