threading: use correct mutex name in reverse_lock fatal error messages

Now that REVERSE_LOCK requires the name of the actual mutex, it can be used for
better error messages.

src/sync.h

@@ -248,7 +248,7 @@ public:
 // it is not possible to use the lock's copy of the mutex for that purpose.
 // Instead, the original mutex needs to be passed back to the reverse_lock for
 // the sake of thread-safety analysis, but it is not actually used otherwise.
-#define REVERSE_LOCK(g, cs) typename std::decay<decltype(g)>::type::reverse_lock UNIQUE_NAME(revlock)(g, cs, #g, __FILE__, __LINE__)
+#define REVERSE_LOCK(g, cs) typename std::decay<decltype(g)>::type::reverse_lock UNIQUE_NAME(revlock)(g, cs, #cs, __FILE__, __LINE__)
 
 // When locking a Mutex, require negative capability to ensure the lock
 // is not already held

src/test/reverselock_tests.cpp

@@ -54,7 +54,7 @@ BOOST_AUTO_TEST_CASE(reverselock_errors)
     g_debug_lockorder_abort = false;
 
     // Make sure trying to reverse lock a previous lock fails
-    BOOST_CHECK_EXCEPTION(REVERSE_LOCK(lock2, mutex2), std::logic_error, HasReason("lock2 was not most recent critical section locked"));
+    BOOST_CHECK_EXCEPTION(REVERSE_LOCK(lock2, mutex2), std::logic_error, HasReason("mutex2 was not most recent critical section locked"));
     BOOST_CHECK(lock2.owns_lock());
 
     g_debug_lockorder_abort = prev;