Include qapi/qmp/qnum.h exactly where needed

Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20180201111846.21846-16-armbru@redhat.com>

tests/check-qlit.c

@@ -12,7 +12,6 @@
 #include "qapi/qmp/qdict.h"
 #include "qapi/qmp/qlist.h"
 #include "qapi/qmp/qlit.h"
-#include "qapi/qmp/qnum.h"
 #include "qapi/qmp/qstring.h"
 
 static QLitObject qlit = QLIT_QDICT(((QLitDictEntry[]) {