Always read CFI section, even when not outputing CFI information.

 On iOS at least, the CFI section contains information needed to
correctly dump the symbols. Even if the CFI section is not dumped,
reading it is necessary to get correcty symbolication.

R=mark@chromium.org, ted.mielczarek@gmail.com

Review URL: https://breakpad.appspot.com/596002

git-svn-id: http://google-breakpad.googlecode.com/svn/trunk@1182 4c0a9323-5329-0410-9bdc-e9ce6186880e