Fix use of File::Temp in tests for File::Temp 0.23

File::Temp had some API changes between 0.22 and 0.23.  Specifically
calling tempfile() and tempdir() will die fatally if you call them as
class methods (File::Temp->tempfile(...).)
Merge branch 'master' of https://github.com/kaoru/File-CleanupTask

Fix use o File::Temp in tests for File::Temp 0.23