💚 update shell syntax

Author: chfw

.moban.d/custom_travis.yml.jj2

@@ -35,6 +35,6 @@ python:
 {%endblock%}
 
 {% block custom_install %}  - if [ -n "$DJANGO_VERSION" ]; then
-      pip install Django==$DJANGO_VERSION
+      pip install Django==$DJANGO_VERSION;
     fi
 {% endblock%}