Allow to set NO_MASQ_LOCAL for weave

[jnummelin]

Setting this up in the config:

network:
  weave:
    no_masq_local: true

$ for node in $NODES; do curl -s $node:$NODEPORT | grep -i client_address; done
client_address=10.38.0.0
client_address=10.32.0.1
client_address=10.44.0.0

$ kubectl patch svc nodeport -p '{"spec":{"externalTrafficPolicy":"Local"}}'
service/nodeport patched

$ for node in $NODES; do curl --connect-timeout 1 -s $node:$NODEPORT | grep -i client_address; done
client_address=91.153.x.y

^ the reported address is my actual address :)

Docs PR: kontena/pharos-docs#147

fixes #1010

[jnummelin]

The option defaults to false to preserve the existing behaviour in existing clusters. Putting it on by default might break network policies etc. for existing clusters.

[jakolehm]

LGTM