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>

gnome-commander.spec

@@ -239,9 +239,6 @@ desktop-file-install \
 
 %find_lang %{name}
 
-%clean
-%{__rm} -rf %{buildroot}
-
 %post
 touch --no-create %{_datadir}/%{name}/mime/packages &> /dev/null
 exit 0