Fix disconnected networks not collapsing on login

Remove call to expandAll() - later calls to setExpandedState() should
automatically expand connected networks.

Before, Qt4 would collapse disconnected networks and expand connected
networks, but Qt5 would always expand both.  After, both collapse
disconnected and expand connected.

Resolves GH-237.

(cherry picked from commit af3b5761f118a0be37f9713e529efd874bf8e11e)