`system_message` from trac.wiki.formatter outputs its second `text` argument in a <PRE> element, but now only if `text` is not `None`.
`system_message` from trac.wiki.formatter outputs its second `text` argument in a <PRE> element, but now only if `text` is not `None`.

git-svn-id: eda3d06fcef731589ace1b284159cead3416df9b@3431 af82e41b-90c4-0310-8c96-b1721e28e2e2

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