Don't raise an internal error when granting an already granted permission or when adding a subject to a group when it was already part of that group. Fixes #3873.
Don't raise an internal error when granting an already granted permission or when adding a subject to a group when it was already part of that group. Fixes #3873.

git-svn-id: eda3d06fcef731589ace1b284159cead3416df9b@5190 af82e41b-90c4-0310-8c96-b1721e28e2e2

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