Refactor the attachment permission code so that new parent resource realms can be more easily added.
Refactor the attachment permission code so that new parent resource realms can be more easily added.

git-svn-id: eda3d06fcef731589ace1b284159cead3416df9b@5561 af82e41b-90c4-0310-8c96-b1721e28e2e2

netjunki/trac-Pygit2,jun66j5/trac-ja,jun66j5/trac-ja,jun66j5/trac-ja,netjunki/trac-Pygit2,walty8/trac,walty8/trac,netjunki/trac-Pygit2,walty8/trac,jun66j5/trac-ja,walty8/trac