ipdb: implement netlink port scan logic
ipdb: implement netlink port scan logic

Move the netlink port scan from NetlinkSocket to the higher level.
A failed NetlinkSocket after `bind()` can not be reused and must
be replaced with a new one.

Bug-Url: https://github.com/svinota/pyroute2/issues/126

drzaeus77/pyroute2,little-dude/pyroute2,nazarewk/pyroute2,simudream/pyroute2,nazarewk/pyroute2,vodik/pyroute2,tomislacker/python-iproute2,roolebo/pyroute2,little-dude/pyroute2,vodik/pyroute2,simudream/pyroute2,roolebo/pyroute2,nazarewk/pyroute2,mtiny/pyroute2,drzaeus77/pyroute2,mtiny/pyroute2,little-dude/pyroute2,tomislacker/python-iproute2