RFR 8168127: FilePermissionCollection merges incorrectly

[Wang Weijun]

Please review the code change at

   http://cr.openjdk.java.net/~weijun/8168127/webrev.00/

Two changes:

1. npath2 is considered in equals and hashCode of FilePermission, so 2 objects with different npath2 can be added to a map and different entries.

2. special name for newPermUsingAltPath and newPermPlusAltPath results, so FilePermissionCollection::add will not merge one with the original.

Thanks
Max