Fix the unit tests due to the PathFSProvider derpage.

Author: marchermans

src/main/java/cpw/mods/niofs/pathfs/PathFileSystemProvider.java

@@ -206,7 +206,7 @@ protected URI buildUriFor(final PathPath path) throws URISyntaxException, Illega
     {
         return new URI(
           path.getFileSystem().provider().getScheme(),
-          path.getFileSystem().getKey() + '~' + this,
+          path.getFileSystem().getKey() + '~' + path,
           null
         );
     }