Nightly not installing sphinx, print TRAVIS_PYTHON_VERSION

Author: rouilj

.travis.yml

@@ -51,11 +51,13 @@ addons:
       - gpgsm
 
 before_install:
+  - echo "$TRAVIS_PYTHON_VERSION"
   # Sphinx required to build the xapian python bindings. Use 1.8.5 on
   # older python and newest on newer.
   - if [[ $TRAVIS_PYTHON_VERSION == "2."* ]]; then pip install sphinx==1.8.5; fi
   - if [[ $TRAVIS_PYTHON_VERSION == "3.[67]" ]]; then pip install sphinx==1.8.5; fi
   - if [[ $TRAVIS_PYTHON_VERSION != "3.[67]" ]] && [[ $TRAVIS_PYTHON_VERSION == '3.'* ]] ; then pip install sphinx; fi
+  - if [[ $TRAVIS_PYTHON_VERSION == "nightly" ]]; then pip install sphinx; fi
   - XAPIAN_VER=$(dpkg -l libxapian-dev | tail -n 1 | awk '{print $3}' | cut -d '-' -f 1)
   - cd /tmp
   - curl -s -O https://oligarchy.co.uk/xapian/$XAPIAN_VER/xapian-bindings-$XAPIAN_VER.tar.xz