correctly check whether weavedns is running and return an error status rather than exit when containers stop just before an HTTP call, which in turn allows us to make tell_dns properly ignore weavedns container absences.
correctly check whether weavedns is running
and return an error status rather than exit when containers stop just
before an HTTP call, which in turn allows us to make tell_dns properly
ignore weavedns container absences.

Fixes #300

BWITS/weave,tomwilkie/weave,paulbellamy/weave,philipz/weave,19hz/weave,tomwilkie/weave,BWITS/weave,ycaihua/weave,errordeveloper/weave,beni55/weave,errordeveloper/weave,rade/weave,inercia/weave,philipz/weave,tomwilkie/weave,awanke/weave,squaremo/weave,paulbellamy/weave,ycaihua/weave,cgvarela/weave,n054/weave,achanda/weave,aaam/weave,errordeveloper/weave,dpw/weave,tomwilkie/weave,awanke/weave,OnePaaS/weave,BWITS/weave,achanda/weave,kidaa/weave,bboreham/weave,kidaa/weave,aaam/weave,paulbellamy/weave,ycaihua/weave,Lawouach/weave,kidaa/weave,paladin74/weave,2opremio/weave,awh/weave,achanda/weave,squaremo/weave,narry/weave,paladin74/weave,awanke/weave,errordeveloper/weave,cgvarela/weave,2opremio/weave,BWITS/weave,OnePaaS/weave,philipz/weave,dpw/weave,inercia/weave,awh/weave,inercia/weave,aaam/weave,2opremio/weave,aaam/weave,narry/weave,errordeveloper/weave,beni55/weave,Lawouach/weave,OnePaaS/weave,kidaa/weave,cgvarela/weave,bboreham/weave,bboreham/weave,weaveworks/weave,paladin74/weave,beni55/weave,weaveworks/weave,squaremo/weave,awanke/weave,OnePaaS/weave,rade/weave,narry/weave,19hz/weave,cgvarela/weave,inercia/weave,Lawouach/weave,paladin74/weave,n054/weave,philipz/weave,ycaihua/weave,aaam/weave,bboreham/weave,beni55/weave,n054/weave,paulbellamy/weave,ycaihua/weave,kidaa/weave,19hz/weave,BWITS/weave,achanda/weave,squaremo/weave,19hz/weave,awh/weave,rade/weave,Lawouach/weave,rade/weave,inercia/weave,dpw/weave,2opremio/weave,tomwilkie/weave,2opremio/weave,dpw/weave,cgvarela/weave,narry/weave,narry/weave,awanke/weave,awh/weave,OnePaaS/weave,dpw/weave,n054/weave,paladin74/weave,philipz/weave,weaveworks/weave,squaremo/weave,beni55/weave,bboreham/weave,awh/weave,rade/weave,achanda/weave,n054/weave,weaveworks/weave