don't exclude _xdg(_unittest)?\\.(h|cc) on OpenBSD either

BUG=
TEST=


Review URL: http://codereview.chromium.org/8558002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@109884 0039d316-1c4b-4281-b951-d872f2087c98

build/common.gypi

@@ -1260,7 +1260,7 @@
               ['exclude', '(^|/)gtk_[^/]*\\.(h|cc)$'],
             ],
           }],
-          ['OS!="linux"', {
+          ['OS!="linux" and OS!="openbsd"', {
             'sources/': [
               ['exclude', '_xdg(_unittest)?\\.(h|cc)$'],
             ],