Add switch to disable IPv6

Add switch to disable IPv6

Due to DualMode, smack deny occurs as ipv4 mapped address is used
for communication between daemon and apps using localhost if internet privilege doesnot exist.

In order to handle the ipv4 mapped loopback in smack, it is necessary to modify the kernel side,
but we cannot know when the patch will be applied.
Also, it is not possible to disable all IPv6 for just solving this issue.

So, set switch to disable ipv6 only when there is no internet privilege.
If there is internet privilege, all works normally in dual mode,
And if there is no internet privilege, ipv6 will be diabled so that local communication can be same as before.