doc: Fix ssl.server.{cert,private_key}.path examples
doc: Fix ssl.server.{cert,private_key}.path examples

Quotes are not needed and they actually force ATS to use a wrong path:
ERROR: failed to load certificate chain from /usr/"/opt/ts/etc/ssl/certs/"/rsa.crt

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