Treat empty content-type header value the same as if it were undefined
Treat empty content-type header value the same as if it were undefined

Clients can send a content-type header with no value and this change
adds handling to treat that case the same as if the header were
undefined. This allows request processing to proceed instead of
resulting in a 500 error response to the user.

srenatus/webmachine,joedevivo/webmachine,chef/webmachine,liuhongchao/webmachine,rabbitmq/webmachine,liuhongchao/webmachine,zkessin/webmachine,mondemand/webmachine,Webmachine/webmachine,amerisoft/webmachine,pooya/webmachine,zkessin/webmachine,agx/webmachine,vinoski/webmachine,rabbitmq/webmachine,mondemand/webmachine,basho/webmachine,neeraj9/webmachine,spilgames/webmachine,voila/webmachine,neeraj9/webmachine,nparry/webmachine,chef/webmachine,anish-mp/webmachine,kbrown/webmachine,pooya/webmachine,raycmorgan/webmachine,rabbitmq/webmachine,boundary/webmachine,i11/webmachine,campanja/webmachine,lemenkov/webmachine,tsloughter/webmachine,i11/webmachine,abanca/webmachine,kellymclaughlin/webmachine,nparry/webmachine,sdebnath/webmachine,riak-synrc/webmachine,samuelrivas/webmachine,basho/webmachine,riak-synrc/webmachine,cmeiklejohn/webmachine,choptastic/webmachine,riak-synrc/webmachine,joedevivo/webmachine,cmeiklejohn/webmachine,amerisoft/webmachine,campanja/webmachine,tsloughter/webmachine,samuelrivas/webmachine,abanca/webmachine,vinoski/webmachine,kellymclaughlin/webmachine,raycmorgan/webmachine,agx/webmachine,lemenkov/webmachine,sdebnath/webmachine,boundary/webmachine,choptastic/webmachine,kbrown/webmachine,NineFX/webmachine,Webmachine/webmachine,anish-mp/webmachine,NineFX/webmachine,voila/webmachine,joedevivo/webmachine,spilgames/webmachine,srenatus/webmachine