Revert "WLAN configuration (static address): reject IPv6 addresses."

This reverts commit 5e1dc560fb898061ebe84de8352917b56dd3ce5d.
Revert "Wifi: Add frequency selection for new IBSS"

This reverts commit 394e0b31e817cf1d8af26303f26ec2924339fff2.
WLAN configuration (static address): reject IPv6 addresses.

Without this, entering an IPv6 address as the interface address (or possibly
also others, such as gateway address) will, on connection to that WLAN,
trigger an uncaught exception:

*** FATAL EXCEPTION IN SYSTEM PROCESS: WifiStateMachine
java.lang.IllegalArgumentException: command '59 interface setcfg wlan0 2001:db8::ffff 24 up' failed with '501 59 Flag unsupported'
	at com.android.server.NetworkManagementService.setInterfaceConfig(NetworkManagementService.java:546)
	at android.net.wifi.WifiStateMachine$ObtainingIpState.enter(WifiStateMachine.java:3449)
	at com.android.internal.util.StateMachine$SmHandler.invokeEnterMethods(StateMachine.java:958)
[etc.]

followed by a restart of the UI then another connection attempt. So long as
the misconfigured-for AP is present (and preferred?), this will continue to
happen.

Change-Id: I524480339c37ad079fd21d90a6b1fc5864089cb5
Signed-off-by: Paul Beeler <sparksco@gmail.com>

Conflicts:
	src/com/android/settings/wifi/WifiConfigController.java