Enable RSN (WPA2) encryption support for IBSS (ad-hoc)

The bug/changes described there were original sent on the mailing list and someone distro patched them in Ubuntu. I'm not familiar with the request nor the changeset but while cleaning up distro patches I digged a bit into that one and figured out it would be good to raise it upstream/get your opinion on the changes.

The Ubuntu bug which did lead to add the patches to our package is https://bugs.launchpad.net/ubuntu/+source/network-manager/+bug/1046918 and has this description

"WPA/WPA2 was disabled for ad-hoc networks because a bug in the kernel breaks WPA-None support (and actually creates networks unsecured rather than encrypted with WPA).

We now have support for actual IBSS-RSN (WPA2 security on ad-hoc) in wpasupplicant and it can be enabled in wpasupplicant, network-manager, nm-applet...

We should make use of this feature to offer our users a way to create properly secured IBSS networks rather than relying on WEP or using unsecured networks.

It will require modifications in three packages:

• network-manager: drop the patch that disables WPA-None (if any) and add the necessary backend bits for using IBSS-RSN.
• network-manager-applet: drop the patch that disables WPA-None (if any) and add the necessary frontend bits to not disable WPA/WPA2; and use IBSS-RSN when WPA/WPA2 is selected for ad-hoc networks.
• wpa: build with CONFIG_IBSS_RSN=y so that IBSS-RSN support gets enabled.

*** While this involves some form of UI changes there is no UIFe request because there are no string changes; the option for WPA/WPA2 has been available since about Maverick, and the change only involves making it sensitive (clickable) again.

Testing was done between two systems; the created network appears secured from both systems and on an external device (used Android phone to detect the network from outside the tested systems; using Wifi-Radar). I've been running the test packages for 6 days; testing was done following the plan at http://wiki.ubuntu.com/NetworkManager/DistroTesting.

Availability of IBSS-RSN can still be dependent on hardware support; in the cases where hardware doesn't support IBSS-RSN; the option will remain disabled in UI."