qapi: Drop pointless flush() before close()

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>

scripts/qapi.py

@@ -1064,9 +1064,5 @@ def close_output(fdef, fdecl):
     fdecl.write('''
 #endif
 ''')
-
-    fdecl.flush()
     fdecl.close()
-
-    fdef.flush()
     fdef.close()