Code review request: 8012615: backport of capaths fix to 7u60

[Weijun Wang]

Hi Valerie

I've backported 8012615 to 7u60. Please take a review

   http://cr.openjdk.java.net/~weijun/8012615/7u-dev/webrev.00/

Changes include:

1. Direct copy of parseCapaths and parseHierarchy from jdk8, except for
   a) use old Config methods
   b) parseCapaths returns null instead of throwing an exception
2. CredentialsUtil.java: no more backwards search, just go thru the path
3. Identical test from jdk8

Thanks
Max