aws sasl: fix doc comment
@@ -102,7 +102,7 @@ func challenge(auth Auth, host string) ([]byte, error) {
v.Set("X-Amz-Algorithm", "AWS4-HMAC-SHA256")
v.Set("X-Amz-Credential", auth.AccessKey+"/"+scope)
v.Set("X-Amz-Date", timestamp)
- v.Set("X-Amz-Expires", "900") // 1 min
+ v.Set("X-Amz-Expires", "900") // 15 min
v.Set("X-Amz-SignedHeaders", "host")
qps := strings.Replace(v.Encode(), "+", "%20", -1)
