Stop doing MIB table dumps under transitter ring lock

They are now done under frontend lock, which still protects against
state changes - which is all that is needed.

Signed-off-by: Paul Durrant <paul.durrant@citrix.com>
Limit MIB table dumps to at most once every 5 seconds

Signed-off-by: Paul Durrant <paul.durrant@citrix.com>
Add more tracing and limit the size of the address table

Signed-off-by: Paul Durrant <paul.durrant@citrix.com>
Merge pull request #40 from pauldu/master

Updates for CA-122017

Approved-By: Ben.Chalmers@citrix.com