Tether: fix bt-pan timing issue

In a situation where bt-pan interface comes up later than the tether
command, tethering will fail with interface not found error. This can
happen when the BT-tethering is quickly and repeatedly enabled and disabled.
Fix is to ignore interface down for these cases

Change-Id: I464b87f1a6470401b2ef4e7507b804b1da5b5af2

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connectivity: Update the logic for running clatd

Enable/disable Android XLAT feature based on persist property
"persist.vendor.net.doxlat". Disabling this property allows hardware
to take over the XLAT functionality.

Change-Id: Iae830e7d74e08161ed8ab1ff0ea50c5b2cb97079

Signed-off-by: "Avinash Thakur <avinasht@codeaurora.org&gt;">
Acked-by: Kaustubh Pandey <kapandey@qti.qualcomm.com>

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Change-Id: Iedde1b1c6a822a01a56244a84ef8ce9c4300245d
CRs-Fixed: 2043773 784379