TS-4198: Restore sync buffer cleanup.
TS-4198: Restore sync buffer cleanup.

This closes #472

chitianhao/trafficserver,davidbz/trafficserver,chitianhao/trafficserver,rahmalik/trafficserver,davidbz/trafficserver,chitianhao/trafficserver,rahmalik/trafficserver,clearswift/trafficserver,clearswift/trafficserver,chenglongwei/trafficserver,PSUdaemon/trafficserver,bryancall/trafficserver,davidbz/trafficserver,clearswift/trafficserver,chenglongwei/trafficserver,chenglongwei/trafficserver,taoyunxing/trafficserver,davidbz/trafficserver,chenglongwei/trafficserver,reveller/trafficserver,PSUdaemon/trafficserver,vmamidi/trafficserver,taoyunxing/trafficserver,rpufky/trafficserver,pbchou/trafficserver,rahmalik/trafficserver,persiaAziz/trafficserver,PSUdaemon/trafficserver,persiaAziz/trafficserver,chenglongwei/trafficserver,reveller/trafficserver,dyrock/trafficserver,PSUdaemon/trafficserver,reveller/trafficserver,persiaAziz/trafficserver,duke8253/trafficserver,SolidWallOfCode/trafficserver,reveller/trafficserver,PSUdaemon/trafficserver,SolidWallOfCode/trafficserver,rpufky/trafficserver,duke8253/trafficserver,PSUdaemon/trafficserver,vmamidi/trafficserver,rahmalik/trafficserver,PSUdaemon/trafficserver,SolidWallOfCode/trafficserver,vmamidi/trafficserver,dyrock/trafficserver,duke8253/trafficserver,rpufky/trafficserver,chenglongwei/trafficserver,davidbz/trafficserver,taoyunxing/trafficserver,bryancall/trafficserver,bryancall/trafficserver,chitianhao/trafficserver,rahmalik/trafficserver,clearswift/trafficserver,rpufky/trafficserver,reveller/trafficserver,persiaAziz/trafficserver,reveller/trafficserver,chitianhao/trafficserver,reveller/trafficserver,SolidWallOfCode/trafficserver,taoyunxing/trafficserver,SolidWallOfCode/trafficserver,dyrock/trafficserver,dyrock/trafficserver,reveller/trafficserver,rahmalik/trafficserver,dyrock/trafficserver,taoyunxing/trafficserver,clearswift/trafficserver,rpufky/trafficserver,rahmalik/trafficserver,PSUdaemon/trafficserver,taoyunxing/trafficserver,dyrock/trafficserver,duke8253/trafficserver,bryancall/trafficserver,rpufky/trafficserver,pbchou/trafficserver,duke8253/trafficserver,taoyunxing/trafficserver,davidbz/trafficserver,clearswift/trafficserver,reveller/trafficserver,chenglongwei/trafficserver,vmamidi/trafficserver,clearswift/trafficserver,dyrock/trafficserver,persiaAziz/trafficserver,bryancall/trafficserver,rahmalik/trafficserver,chitianhao/trafficserver,SolidWallOfCode/trafficserver,persiaAziz/trafficserver,chenglongwei/trafficserver,clearswift/trafficserver,duke8253/trafficserver,rpufky/trafficserver,persiaAziz/trafficserver,PSUdaemon/trafficserver,chitianhao/trafficserver,duke8253/trafficserver,pbchou/trafficserver,SolidWallOfCode/trafficserver,clearswift/trafficserver,taoyunxing/trafficserver,pbchou/trafficserver,persiaAziz/trafficserver,taoyunxing/trafficserver,vmamidi/trafficserver,rahmalik/trafficserver,bryancall/trafficserver,rpufky/trafficserver,vmamidi/trafficserver,rpufky/trafficserver,pbchou/trafficserver,pbchou/trafficserver