[2.11.x] Yum work

https://issues.sonatype.org/browse/NEXUS-6801
https://issues.sonatype.org/browse/NEXUS-6790
http://issues.sonatype.org/browse/NEXUS-6702

http://bamboo.s/browse/NX-OSSF305
Can `pos + memberRepoDirPath.length()` ever be longer than href given pos is `href.indexOf(memberRepoDirPath)`?