Maid 22 bad alloc

https://maidsafe.atlassian.net/browse/MAID-22

the verification involves using routing_node network across droplets

it may worth to check whether the routing_node network (using next branch) suffers the same issue as using interim_merge_of_unsafe_packet_loss_tolerance branch.
If not, then no need to merge this MAID-22_bad_alloc branch into next.

I am not sure here.
Running multiple vaults on same machine not using symmetric NAT does have issues in previous handling.
However, as you pointed out, this fix may block the usage that running multiple vaults on same machine using symmetric NAT.

This block code may need to be marked as temp fix, as I just committed it to allow a routing_node network can be setup properly across droplets.