FIX: buildbot: install django<2 if python2 is used.

.buildbot/deploy/01-requirements.sh

@@ -1 +1,5 @@
+python_major_version=`python -c 'import sys; print sys.version_info.major'`
+if test "$python_major_version" = "2" ; then
+	pip install 'django<2'
+fi
 pip install -r requirements.txt

.buildbot/test/01-requirements.sh

@@ -1 +1,5 @@
+python_major_version=`python -c 'import sys; print sys.version_info.major'`
+if test "$python_major_version" = "2" ; then
+	pip install 'django<2'
+fi
 pip install -r requirements.txt