D11013: Detect incorrect paramenter in findProtocol

[Jaime Torres Amate]

jtamate added a dependent revision: D11044: Don't try to find an icon for an 
empty url.

REPOSITORY
  R241 KIO

REVISION DETAIL
  https://phabricator.kde.org/D11013

To: jtamate, #frameworks, dfaure
Cc: michaelh