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

.travis.yml

@@ -18,6 +18,7 @@ matrix:
       env: JYTHON=jython-installer:2.5.3 BACKEND=hsqldb
 
 before_install:
+  - export -f deactivate
   - ci/before_install.sh
   - source ~/myvirtualenv/bin/activate
 

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)")