Fix a pipelining bug that occurs if we push in a request while we are processing another request that is not completed.
Fix a pipelining bug that occurs if we push in a request while we are
processing another request that is not completed.

* context.c
  (read_from_connection): If we switched to a new request, update the
  pollset unconditionally.  Otherwise, the pollset might not know that
  we have data to write this time around.

wzugang/serf,stoneCC/serf,soufianeEL/serf,justinweb/serf,blueszhangsh/serf,SirJson/serf,x-clone/serf,pengdu/serf,yesoce/serf,SirJson/serf,muthusuba/serf,x-clone/serf,alex1818/serf,liuzongquan/serf,TommyU/serf,liuzongquan/serf,Manouchehri/serf,pengdu/serf,lazysoez/serf,liuzongquan/serf,stoneCC/serf,lazysoez/serf,blueszhangsh/serf,KyleSanderson/serf,idomon/serf,google-code-export/serf,Manouchehri/serf,KyleSanderson/serf,SirJson/serf,yesoce/serf,sworda/serf,stoneCC/serf,idomon/serf,krime/serf,Manouchehri/serf,lazysoez/serf,liuzongquan/serf,soufianeEL/serf,idomon/serf,yesoce/serf,wzugang/serf,TommyU/serf,justinweb/serf,muthusuba/serf,sworda/serf,TommyU/serf,zhengcq315/serf,SirJson/serf,sworda/serf,pengdu/serf,zhupan/serf,KyleSanderson/serf,zhupan/serf,krime/serf,x-clone/serf,Manouchehri/serf,wzugang/serf,alex1818/serf,zhengcq315/serf,soufianeEL/serf,justinweb/serf,google-code-export/serf,blueszhangsh/serf,stoneCC/serf,muthusuba/serf,KyleSanderson/serf,google-code-export/serf,pengdu/serf,muthusuba/serf,krime/serf,zhengcq315/serf,idomon/serf,zhupan/serf,lazysoez/serf,krime/serf,zhengcq315/serf,alex1818/serf,sworda/serf,alex1818/serf,blueszhangsh/serf,zhupan/serf,justinweb/serf,google-code-export/serf,soufianeEL/serf,x-clone/serf,wzugang/serf,TommyU/serf,yesoce/serf