Setting SO_MARK to MARK_UNSET, ie. 0, is harmless,
since the default for a brand new socket is already 0.
See ClatCoordinator.java getFwMark() for the mark we actually pass in,
which is guaranteed to have at least 4 bits (16,17,18,19) set.
See also:
https://android-review.git.corp.google.com/c/platform/packages/modules/Connectivity/+/2392272
Signed-off-by: Maciej Żenczykowski <maze@google.com>
Change-Id: I3b4eebc0a5ad20390a13efcc58cecf94868686ba
8bf5967d1e