Valgrind memory analyzer fails silently if valgrind isn't installed

If a user clicks on the menu entry "Analyze" -> "Valgrind memory analyzer" when Valgrind isn't installed, Qt Creator simply pops open a blank terminal window and does nothing.

It would be nice if Qt Creator performed any kind of sanity check on its dependencies before making them available to the user, and more importantly enabled users to be aware of what steps they can take to get Qt Creator to work.