[#741,!428] Fixed doxygen errors

Fixed two minor doxygen errors:
    src/hooks/dhcp/high_availability/ha_service.h
    src/lib/http/client.h

src/hooks/dhcp/high_availability/ha_service.h

@@ -734,7 +734,7 @@ protected:
     ///
     /// @param ec Error status of the ASIO connect
     /// @param tcp_native_fd socket descriptor to register
-    /// @param returns true. Registeration cannot fail, and if ec indicates a real
+    /// @return always true. Registeration cannot fail, and if ec indicates a real
     /// error we want Connection logic to process it.
     bool clientConnectHandler(const boost::system::error_code& ec, int tcp_native_fd);
 

src/lib/http/client.h

@@ -173,6 +173,8 @@ public:
     /// @param request_timeout Timeout for the transaction in milliseconds.
     /// @param connect_callback Optional callback invoked when the client
     /// connects to the server.
+    /// @param close_callback Optional callback invoked when the client
+    /// closes the connection to the server.
     ///
     /// @throw HttpClientError If invalid arguments were provided.
     void asyncSendRequest(const Url& url,