silence more warnings

R=rsc
http://codereview.appspot.com/6744056

src/cmd/auth/factotum/p9cr.c

@@ -65,6 +65,7 @@ p9crclient(Conv *c)
 	res = nil;
 	ret = -1;
 	attr = c->attr;
+	astype = -1;
 
 	if(c->proto == &p9cr){
 		astype = AuthChal;
@@ -131,6 +132,7 @@ p9crclient(Conv *c)
 	ret = 0;
 
 out:
+	USED(astype);
 	keyclose(k);
 	if(c->attr != attr)
 		freeattr(attr);

src/cmd/auth/rsa2any.c

@@ -164,7 +164,6 @@ getdsakey(int argc, char **argv, int needprivate, Attr **pa)
 	char *file, *s, *p;
 	DSApriv *key;
 	Biobuf *b;
-	int regen;
 	Attr *a;
 
 	if(argc == 0)
@@ -190,7 +189,6 @@ getdsakey(int argc, char **argv, int needprivate, Attr **pa)
 		return nil;
 	}
 
-	regen = 0;
 	a = _parseattr(s+4);
 	if(a == nil){
 		werrstr("empty key");

src/cmd/auth/ssh-agent.c

@@ -973,6 +973,7 @@ runmsg(Aconn *a)
 
 	case SSH_AGENTC_RSA_CHALLENGE:
 		n = get4(&m);
+		USED(n);
 		ek = getmp(&m);
 		mod = getmp(&m);
 		chal = getmp(&m);