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>

setroubleshoot.spec

@@ -123,9 +123,6 @@ getent passwd %{username} >/dev/null || useradd -r -U -s /sbin/nologin -d %{pkgv
 %triggerun server -- %{name}-server < 3.2.24-4
 chown -R setroubleshoot:setroubleshoot %{pkgvardatadir}
 
-%clean
-rm -rf %{buildroot}
-
 %files server -f %{name}.lang
 %{_bindir}/sealert
 %{_sbindir}/sedispatch