audio: Convert use of atoi to qemu_strtoi

If qemu_strtoi indicates an error, return the default value.
Signed-off-by: NNia Alarie <nia.alarie@gmail.com>
Message-Id: <20180316144047.30904-1-nia.alarie@gmail.com>
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>

audio/audio.c

@@ -335,9 +335,8 @@ static int audio_get_conf_int (const char *key, int defval, int *defaultp)
     char *strval;
 
     strval = getenv (key);
-    if (strval) {
+    if (strval && !qemu_strtoi(strval, NULL, 10, &val)) {
         *defaultp = 0;
-        val = atoi (strval);
         return val;
     }
     else {