Coverity 11892: in class Stop, address lock-free access to stop_calle…

…d member

In class Stop, the stop_called member is safe to read
without locking, but make it volatile to document this.

Signed-off-by: James Yonan <james@openvpn.net>

openvpn/common/stop.hpp

@@ -125,7 +125,7 @@ class Stop
 
  std::recursive_mutex mutex;
  std::vector<Scope *> scopes;
- bool stop_called = false;
+ volatile bool stop_called = false;
 };
 
 } // namespace openvpn