cppcheck: Use initialization list instead of assigning in constructor body
cppcheck: Use initialization list instead of assigning in constructor body

> [Http2ClientSession.h:77]: (performance) Variable 'hdr' is assigned in constructor body. Consider performing initialization in initialization list.
> [Http2ClientSession.h:83]: (performance) Variable 'hdr' is assigned in constructor body. Consider performing initialization in initialization list.

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