Replace broken WMS demo URLs with working URLs

I'd liked to add a UMN MapServer Demo too but
I couldn't find a working one.

Backported from master.

Author: elpaso

src/providers/wms/qgswmssourceselect.cpp

@@ -1095,10 +1095,8 @@ QString QgsWMSSourceSelect::descriptionForAuthId( const QString& authId )
 void QgsWMSSourceSelect::addDefaultServers()
 {
   QMap<QString, QString> exampleServers;
-  exampleServers["DM Solutions GMap"] = "http://www2.dmsolutions.ca/cgi-bin/mswms_gmap";
-  exampleServers["Lizardtech server"] =  "http://wms.lizardtech.com/lizardtech/iserv/ows";
-  // Nice to have the qgis users map, but I'm not sure of the URL at the moment.
-  //  exampleServers["Qgis users map"] = "http://qgis.org/wms.cgi";
+  exampleServers["QGIS Server Demo - Alaska"] = "http://demo.qgis.org/cgi-bin/qgis_mapserv.fcgi?map=/web/demos/alaska/alaska_map.qgs";
+  exampleServers["GeoServer Demo - World"] = "http://tiles.boundlessgeo.com/";
 
   QSettings settings;
   settings.beginGroup( "/Qgis/connections-wms" );