[TS-4160] Reset the txn request/response handles at each hook, since core may destroy them.
[TS-4160] Reset the txn request/response handles at each hook, since core may destroy them.

[TS-4160] clean up the code and initialize all handles for all hooks.

[TS-4160] move the reset of handles to NULL to the operator() from TS-4135.

[TS-4160] remove unnecessary reset.

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