Warning from the Sparse static analysis tool:

stubs/qtest.c:14:6:
 warning: symbol 'qtest_allowed' was not declared. Should it be static?

Add the missing include statement which declares qtest_allowed.

Signed-off-by: Stefan Weil <sw@weilnetz.de>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>