bug patterns need to escape parentheses

We've discovered that when writing bug patterns it isn't necessary to escape parens "()" in the Title and OriginalTitle key of bug patterns. For example:

<pattern url="https://launchpad.net/bugs/832745">
<re key="Package">^update-manager </re>
<re key="OriginalTitle">update-manager crashed with TypeError in confirmChanges\(\)</re>
<re key="Traceback">TypeError: glib.markup_escape_text\(\) takes at most 1 argument \(2 given\)</re>
</pattern>

The pattern above matches when used with test-local from the bugpatterns branch (rev 329) and so does:

<pattern url="https://launchpad.net/bugs/832745">
<re key="Package">^update-manager </re>
<re key="OriginalTitle">update-manager crashed with TypeError in confirmChanges()</re>
<re key="Traceback">TypeError: glib.markup_escape_text\(\) takes at most 1 argument \(2 given\)</re>
</pattern>

However, if one were to remove the escaping of parens in the Traceback key of the pattern the pattern would not match. This makes little sense and inspecting the code of both test-local and the "_check_bug_pattern" function of apport/report.py gives no indication why this might be.

ProblemType: Bug
DistroRelease: Ubuntu 11.10
Package: apport 1.22.1-0ubuntu2
ProcVersionSignature: Ubuntu 3.0.0-10.16-generic 3.0.4
Uname: Linux 3.0.0-10-generic x86_64
ApportLog:

ApportVersion: 1.22.1-0ubuntu2
Architecture: amd64
CheckboxSubmission: fee5e196cb921cbd36888f428b38b488
CheckboxSystem: 2a6f54df59af338184485e85cbcf0d32
Date: Fri Sep 9 08:26:57 2011
PackageArchitecture: all
ProcEnviron:
 PATH=(custom, user)
 LANG=en_US.UTF-8
 SHELL=/bin/zsh
SourcePackage: apport
UpgradeStatus: Upgraded to oneiric on 2011-09-06 (2 days ago)