1.0.3dev: Avoid unnecessary bracket in extacted message. Refs #11804.

The issue was introduced in [13237]. Patch by Jun Omae.


git-svn-id: http://trac.edgewall.org/intertrac/log:/branches/1.0-stable@13239 af82e41b-90c4-0310-8c96-b1721e28e2e2