Fix enabling menu bar multiple times on Haiku

Fix enabling menu bar multiple times on Haiku

* src/haiku_support.cc (FrameResized): Adjust width and height
appropriately when sending menu bar resize event.
* src/haikufns.c (haiku_set_menu_bar_lines): Don't always reset
FRAME_MENU_BAR_LINES and FRAME_MENU_BAR_HEIGHT.
* src/haikumenu.c (free_frame_menubar): Clear Haiku menu bar.
(set_frame_menubar): Fix coding style.
* src/haikuterm.c (haiku_read_socket): Don't adjust height here
anymore.