Attach log file instead of appending it to description

If we don't have a log file we append the line "No log available" to
the description, otherwise we attach the log file to the jira issue.

Also don't show reporter dialog on taskbar (which otherwise shows up as question mark on Linux).
It's a modal dialog, so it always sits in front of Bloom. Thus clicking on the normal Bloom icon will reveal the dialog as well.