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>

evolution-data-server.spec

@@ -266,9 +266,6 @@ find $RPM_BUILD_ROOT -name '*.so.*' -exec chmod +x {} \;
 
 %find_lang %{name}
 
-%clean
-rm -rf $RPM_BUILD_ROOT
-
 %post -p /sbin/ldconfig
 
 %postun