KProtocolInfo: don't call KProtocolInfo::archiveMimetypes() on an empty string
archiveMimetypes() calls findProtocol(), which asserts the url scheme isn't empty.
This fixes the KUrlNavigator unit test.
Edited by Ahmad Samir
archiveMimetypes() calls findProtocol(), which asserts the url scheme isn't empty.
This fixes the KUrlNavigator unit test.