Uses a top-level temporary directory
Uses a top-level temporary directory

This allows the test suite to clean up the temporary files if the tests
leave some behind.

A warning is shown, currently on stdout, not stderr, so it shouldn't
cause buildbots to report failure.

Nikea/VisTrails,hjanime/VisTrails,minesense/VisTrails,celiafish/VisTrails,hjanime/VisTrails,hjanime/VisTrails,minesense/VisTrails,VisTrails/VisTrails,minesense/VisTrails,hjanime/VisTrails,Nikea/VisTrails,celiafish/VisTrails,Nikea/VisTrails,celiafish/VisTrails,celiafish/VisTrails,VisTrails/VisTrails,Nikea/VisTrails,VisTrails/VisTrails,VisTrails/VisTrails,hjanime/VisTrails,VisTrails/VisTrails,minesense/VisTrails,minesense/VisTrails