Revert content type of timeline RSS feed that I changed for debugging purposes in [1597].
Revert content type of timeline RSS feed that I changed for debugging purposes in [1597].

git-svn-id: eda3d06fcef731589ace1b284159cead3416df9b@1601 af82e41b-90c4-0310-8c96-b1721e28e2e2

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