Fixes bug 333076 parley and dolphin crash simultaneously when images

 are dragged from dolphin to parley

Problem: Some dragdrop events don't contain any urls. The previous code assumed that all events contain at least one url and would crash when it accessed the non-existent QList[0] item.

Patch: Checks that there is at least 1 url before using the first url.

Note: I was unable to crash dolphin, but I think this is the same bug because the crash occurs on the exact same line as in Ansa's backtrace

BUG: 333076

REVIEW: 119125