KUrlRequester: fix error box when selecting a file and reopening the file dialog.
Review Request #128675 - Created Aug. 13, 2016 and submitted
"<foo> is a file, but a folder was expected" was shown because of the setDirectoryUrl() call added in 580dfd4992ca7d1d4 to fix bug 364719. This is nowadays unnecessary, apparently due to commit 18e62e7 in plasma-integration, selectUrl() does the right thing including changing dirs. The new unittest shows that this works, and that the error above doesn't happen anymore.
The much improved unittest now passes.