Fix passing a URL key/value containing %26 (escaped &)

It seems that this code *only* deals with Parameters in the URL (maybe on POST
too), but not in SOAP requests from UPnP clients.  It should be a benign
change to not mess with %26 in the params string before splitting on &.  Any
self-respecting client will know that & separates the keys, and not to escape
them.  If this breaks any specific clients, we will have to put in a workaround
for the broken client perhaps.

Fixes #8132.

mythtv/libs/libmythupnp/httprequest.cpp

@@ -837,7 +837,11 @@ long HTTPRequest::GetParameters( QString sParams, QStringMap &mapParams  )
 {
     long nCount = 0;
 
-    sParams.replace( "%26", "&" );
+    VERBOSE(VB_UPNP|VB_EXTRA, QString("sParams: '%1'").arg(sParams));
+
+    // This looks odd, but it is here to cope with stupid UPnP clients that
+    // forget to de-escape the URLs.  We can't map %26 here as well, as that
+    // breaks anything that is trying to pass & as part of a name or value.
     sParams.replace( "&", "&" );
 
     if (sParams.length() > 0)