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-Class-Trigger.spec

@@ -51,9 +51,6 @@ chmod -R u+w $RPM_BUILD_ROOT/*
 %check
 make test
 
-%clean
-rm -rf $RPM_BUILD_ROOT
-
 %files
 %defattr(-,root,root,-)
 %doc Changes README