Merge branch 'erspan-fixes'

William Tu says:

====================
a couple of erspan fixes

The series fixes a couple of erspan issues.
The first patch adds the erspan v2 proto type to the ip6 tunnel lookup.
The second patch improves the error handling when users screws the
version number in metadata.  The final patch makes sure the skb has
enough headroom for pushing erspan header when xmit.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>