Fix unit test failure: TestNeighAddDelLLIPAddr
Fix unit test failure: TestNeighAddDelLLIPAddr

TestNeighAddDelLLIPAddr was failing due to the Neighbour table
not getting properly populated when using a ipip tunnel.
This matches the behaviour in the latest kernel when using
the ip command.

Switch the tunnel type to a gre point to multi-point tunnel.
The neighbour table gets properly populated in this case.

Signed-off-by: Manohar Castelino <f32964ad29a31ea3feb8b48f3bb1748edf23aee2@intel.com>

vishvananda/netlink,paravmellanox/netlink