fix: Fixed the bug that prevented the correct identification of upnp …

[Droid-MAX]

…devices

[Droid-MAX]

I think that in most legal response fields, apart from the two headers "LOCATION" and "Location", other situations basically do not occur, and in the response body, only lowercase http protocol headers will basically appear.

[MikeWang000000]

apart from the two headers "LOCATION" and "Location"

Even Location is not common in SSDP messages. All header names in UPnP Device Architecture 1.0 is all-uppercase (e.g. LOCATION, not Location). It specifies All header values are case sensitive except where noted without mentioning header names. Tough the later one v2.0 additionally clarifies that the header name is case-insensitive, many implementations like miniupnp still uses the all-uppercase form.

But when we decide to fix this rare case, we should also take other corner cases into consideration as well. Functions like split_url() should also be fixed.