CopyLinkToClipboard should copy the URL only

The addition of title information to the dragged or copied links, has
caused the clipboard after CopyLinkToClipboard to paste the link title
instead of the link URL when doing a simple paste.

This paste removes the title from the MimeData so that QMimeData must
return the text version of the URL when pasting text.

Task-number: QTBUG-39341
Change-Id: Ia28ea0f0eda07a4133c5628b60db624a16ed9931
Reviewed-by: Michael Bruning <michael.bruning@digia.com>