TS-2553: minor metalink refactoring
TS-2553: minor metalink refactoring

Reorder some functions so related functions are grouped together.
Rename some variables to more easily disambiguate them.

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