webrtc: Remove semicolons.

Bug: chromium:926235
Change-Id: I66c10ab3df38adf87152d1f18cc8162afedca7e4
Reviewed-on: https://webrtc-review.googlesource.com/c/123560
Commit-Queue: Tommi <tommi@webrtc.org>
Reviewed-by: Tommi <tommi@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#26780}

system_wrappers/include/clock.h

@@ -83,6 +83,6 @@ class SimulatedClock : public Clock {
   std::unique_ptr<RWLockWrapper> lock_;
 };
 
-};  // namespace webrtc
+}  // namespace webrtc
 
 #endif  // SYSTEM_WRAPPERS_INCLUDE_CLOCK_H_