fix error: ‘reverse_lock’ is not a member of ‘boost’

[rhaschke]

Obviously a recent change in boost, makes actionlib fail due to a missing boost include:

/opt/ros/kinetic/include/actionlib/server/action_server_base.h: In member function ‘void actionlib::ActionServerBase<ActionSpec>::goalCallback(const boost::shared_ptr<const typename ActionSpec::_action_goal_type>&)’:
/opt/ros/kinetic/include/actionlib/server/action_server_base.h:256:5: error: ‘reverse_lock’ is not a member of ‘boost’
     boost::reverse_lock<boost::recursive_mutex::scoped_lock> unlocker(lock);

This PR adds the missing include, which is definitely not part of any standard boost include anymore:

$ grep -r reverse_lock /usr/include/boost/thread
/usr/include/boost/thread/reverse_lock.hpp:    class reverse_lock
/usr/include/boost/thread/reverse_lock.hpp:        BOOST_THREAD_NO_COPYABLE(reverse_lock)
/usr/include/boost/thread/reverse_lock.hpp:        explicit reverse_lock(Lock& m_)
/usr/include/boost/thread/reverse_lock.hpp:        ~reverse_lock()
/usr/include/boost/thread/reverse_lock.hpp:    struct is_mutex_type<reverse_lock<T> >

[mikaelarguedas]

thanks @rhaschke for catching this.

I think it's actually a recent change in actionlib that introduced that error, looking at boost's history it doesnt look like reverse_lock was included in thread.hpp in previous boost versions either. I guess we didnt catch it earlier because no one was using the action_server_base.h directly but the action_server.h instead. Is that the scenario in which you faced this issue ?

[rhaschke]

Indeed we face the mentioned use case. I was suprised that we didn't catch this error earlier. Obviously the corresponding libs weren't rebuilt for a while.

[mikaelarguedas]

thanks @rhaschke
I'm going to merge this and audit the other files to make sure we "include what we use"