Freeze break: gnome-shell: keep the connection list visible when connecting

[Owen Taylor <otaylor redhat com>]

Right now, when you try to connect to a wireless network, what you see
is:

- All wireless networks vanish and you just see the Wireless header
- When the connection definitely fails or succeeds, the wireless
  networks come back.

This isn't too bad in normal operation, but if something goes wrong
and the user clicks on the menu to see what is going on, it's pretty
confusing.

https://bugzilla.gnome.org/show_bug.cgi?id=646381

Changes are generally agreed upon and I've given it pretty extensive
testing.

- Owen