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* serf_private.h
  (struct serf_connection_t): Clarify host_url and host_info usage.

Manouchehri/serf,TommyU/serf,wzugang/serf,blueszhangsh/serf,sworda/serf,idomon/serf,blueszhangsh/serf,liuzongquan/serf,justinweb/serf,wzugang/serf,muthusuba/serf,liuzongquan/serf,sworda/serf,muthusuba/serf,sworda/serf,wzugang/serf,TommyU/serf,krime/serf,Manouchehri/serf,liuzongquan/serf,Manouchehri/serf,idomon/serf,blueszhangsh/serf,blueszhangsh/serf,justinweb/serf,krime/serf,krime/serf,TommyU/serf,krime/serf,muthusuba/serf,wzugang/serf,idomon/serf,liuzongquan/serf,justinweb/serf,TommyU/serf,sworda/serf,justinweb/serf,idomon/serf,Manouchehri/serf,muthusuba/serf