Remove %clean section

None of currently supported distributions need that.
Last one was EL5 which is EOL for a while.

Signed-off-by: Igor Gnatenko <ignatenkobrain@fedoraproject.org>

perl-Test-Distribution.spec

@@ -49,9 +49,6 @@ rm -rf %{buildroot}
 %check
 ./Build test
 
-%clean
-rm -rf %{buildroot}
-
 %files
 %doc Changes.pod README
 %{perl_vendorlib}/Test/