Bad error message on WFS connection fail

[qgib]

Author Name: Jonathan Moules (Jonathan Moules)
Original Redmine Issue: 22052
Affected QGIS version: 3.4.3
Redmine category:web_services_clients/wfs

---

I was trying to connect to a WFS but my firewall was blocking QGIS.

I expect QGIS to come back with a meaningful message, but instead I get back:
"unexpected[sic] end of file"

This is meaningless to an end user. It's also clearly erroring out at the wrong place - something should be catching the lack of connection well before it ever tries to parse the getcap.

[qgib]

Author Name: Jonathan Moules (Jonathan Moules)

---

You get a bad message if you request the wrong type of service.

Use this for WFS:
http://ags.kr-plzensky.cz/arcgis/services/UPD/Stod/MapServer/WmsServer

You'll get back an exception:
"Can't recognize service requested."

but QGIS represents this as:
"Service contains no layers" - which is less useful and certainly less correct than passing on the exception message