gas gen-sframe memory leaks

More freeing required.

	* gen-sframe.c (all_sframe_fdes, last_sframe_fde): Move earlier,
	make file scope.
	(sframe_row_entry_new): Move earlier.
	(sframe_row_entry_free): New function.
	(sframe_fde_alloc, sframe_fde_free): Move earlier.
	(sframe_fde_link): Delete.  Expand into..
	(create_sframe_all): ..here.
	(output_sframe_internal): Delete silly sframe_flags init.
	Free fdes.  Reset static vars.
	(sframe_xlate_ctx_cleanup): Use sframe_row_entry_free.  Free
	remember_fre too.  Don't re-init xlate_ctx we're about to drop.
	* gen-sframe.h (all_sframe_fdes): Don't declare.