spf exists queries were using the wrong type of question.
it's not "a" it's "ip".

Reference: /n/atom/patch/applied/spfipnota
Date: Wed Feb 26 16:00:13 CET 2014
Signed-off-by: quanstro@quanstro.net

--- /sys/src/cmd/upas/spf/spf.c	Wed Feb 26 15:58:58 2014
+++ /sys/src/cmd/upas/spf/spf.c	Wed Feb 26 15:58:59 2014
@@ -400,7 +400,7 @@
 {
 	Ndbtuple *t;
 
-	if(t = vdnsquery(d, "a", recur))
+	if(t = vdnsquery(d, "ip", recur))
 		spfadd(Texists, "1");
 	else
 		spfadd(Texists, 0);