Unhook current Breakpad object after handling uncaught NSException.

After handling an uncaught NSException, release the Breakpad object
so there will not be a second crash dump logged.

Prior to this change, for every uncaught NSException handled through
the Breakpad::UncaughtExceptionHandler(), a second crash without
any useful information (generally __cxa_rethrow and std::__terminate)
is recorded.

R=qsr@chromium.org

Review URL: https://breakpad.appspot.com/9664002

Patch from Peter Lee <pkl@chromium.org>.

git-svn-id: http://google-breakpad.googlecode.com/svn/trunk@1344 4c0a9323-5329-0410-9bdc-e9ce6186880e
Fix compilation error in Linux libc++ builds due to use of tr1/.

Patch by Sergey Matveev <earthdok@chromium.org>

BUG=chromium:391792

Review URL: https://breakpad.appspot.com/7674002/


git-svn-id: http://google-breakpad.googlecode.com/svn/trunk@1345 4c0a9323-5329-0410-9bdc-e9ce6186880e