Doc: Remove pipeline references
Doc: Remove pipeline references

Issue #3712 points out that its unlikely that http1.1 pipelining is not
working. Options were removed for it a while back. Similarly,
support for http 0.9 has been removed.

bryancall/trafficserver,chitianhao/trafficserver,chitianhao/trafficserver,vmamidi/trafficserver,SolidWallOfCode/trafficserver,dyrock/trafficserver,duke8253/trafficserver,davidbz/trafficserver,duke8253/trafficserver,bryancall/trafficserver,vmamidi/trafficserver,pbchou/trafficserver,pbchou/trafficserver,dyrock/trafficserver,duke8253/trafficserver,SolidWallOfCode/trafficserver,chitianhao/trafficserver,vmamidi/trafficserver,duke8253/trafficserver,SolidWallOfCode/trafficserver,bryancall/trafficserver,bryancall/trafficserver,vmamidi/trafficserver,davidbz/trafficserver,pbchou/trafficserver,chitianhao/trafficserver,dyrock/trafficserver,vmamidi/trafficserver,dyrock/trafficserver,duke8253/trafficserver,pbchou/trafficserver,duke8253/trafficserver,chitianhao/trafficserver,vmamidi/trafficserver,pbchou/trafficserver,davidbz/trafficserver,chitianhao/trafficserver,SolidWallOfCode/trafficserver,SolidWallOfCode/trafficserver,pbchou/trafficserver,davidbz/trafficserver,dyrock/trafficserver,bryancall/trafficserver,dyrock/trafficserver,dyrock/trafficserver,davidbz/trafficserver,bryancall/trafficserver,chitianhao/trafficserver,davidbz/trafficserver,SolidWallOfCode/trafficserver,duke8253/trafficserver,SolidWallOfCode/trafficserver