tests 1348 to 1363: test definition polishing

Verify that the "Saved to filename 'blabla'" message is only displayed when
the 'blabla' filename being used _actually_ has been specified by the server
in the Content-Disposition header.

Use relative path for unintended file creation postcheck.

tests/data/test1339

@@ -68,7 +68,6 @@ Content-Length: 6
 Connection: close
 Content-Type: text/html
 
-curl: Saved to filename '%PWD/log/1339'
 </file2>
 
 </verify>