[patch] fix schnorr vasprintf warnings on openssh-SNAP-20130304

[g.esp at free.fr]

Tested against openssh-SNAP-2013-03-04

Fix those 2 old warnings
schnorr.c: In function 'debug3_bn':
schnorr.c:494: warning: ignoring return value of 'vasprintf', declared with attribute warn_unused_result
schnorr.c: In function 'debug3_buf':
schnorr.c:519: warning: ignoring return value of 'vasprintf', declared with attribute warn_unused_result

vasprintf return value should be checked.
If an error happen, -1 is returned and first parameter is undefined

--- openssh/schnorr.c.orig	2010-12-04 23:00:30.000000000 +0100
+++ openssh/schnorr.c	2013-03-03 23:35:11.000000000 +0100
@@ -491,10 +491,9 @@
 
 	out = NULL;
 	va_start(args, fmt);
-	vasprintf(&out, fmt, args);
-	va_end(args);
-	if (out == NULL)
+	if (vasprintf(&out, fmt, args) == -1)
 		fatal("%s: vasprintf failed", __func__);
+	va_end(args);
 
 	if (n == NULL)
 		debug3("%s(null)", out);
@@ -516,10 +515,9 @@
 
 	out = NULL;
 	va_start(args, fmt);
-	vasprintf(&out, fmt, args);
-	va_end(args);
-	if (out == NULL)
+	if (vasprintf(&out, fmt, args) == -1)
 		fatal("%s: vasprintf failed", __func__);
+	va_end(args);
 
 	debug3("%s length %u%s", out, len, buf == NULL ? " (null)" : "");
 	free(out);

Gilles