Try to export the virtualenv deactivate function as we want to deactivate it for Jython builds

ci/before_install_jython.sh

@@ -5,6 +5,7 @@ pip install jip==0.7
 jip install org.python:$JYTHON
 _JYTHON_BASENAME=${JYTHON/:/-}
 OLD_VIRTUAL_ENV=$VIRTUAL_ENV
+deactivate
 java -jar $OLD_VIRTUAL_ENV/javalib/${_JYTHON_BASENAME}.jar -s -d ~/jython
 touch requirements.txt
 BEFORE_PY_26=$(~/jython/bin/jython -c "import sys; print sys.version_info < (2, 6)")