crash-reporter: Use C++11 override specifier.

Also remove some unnecessary 'void' arguments.

BUG=None
TEST=`FEATURES=test emerge-$BOARD crash-reporter`

Change-Id: I0039aec93aae14cb238f284fda756b631f9c1587
Reviewed-on: https://chromium-review.googlesource.com/211959
Reviewed-by: Mike Frysinger <vapier@chromium.org>
Commit-Queue: Ben Chan <benchan@chromium.org>
Tested-by: Ben Chan <benchan@chromium.org>
diff --git a/crash_reporter/udev_collector.h b/crash_reporter/udev_collector.h
index e54ce5b..2b9bd34 100644
--- a/crash_reporter/udev_collector.h
+++ b/crash_reporter/udev_collector.h
@@ -17,7 +17,7 @@
  public:
   UdevCollector();
 
-  virtual ~UdevCollector();
+  ~UdevCollector() override;
 
   // The udev event string should be formatted as follows:
   //   "ACTION=[action]:KERNEL=[name]:SUBSYSTEM=[subsystem]"