Remove extra semicolons:

Several functions had an extra semicolon. This removes them.

src/test/rpc/Book_test.cpp

@@ -1094,7 +1094,7 @@ public:
             return false;
         // Make sure no other message is waiting
         return wsc->getMsg(timeout) == boost::none;
-    };
+    }
 
     void
     testCrossingSingleBookOffer()