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>

mythes.spec

@@ -39,9 +39,6 @@ rm -f $RPM_BUILD_ROOT/%{_libdir}/*.a
 rm -f $RPM_BUILD_ROOT/%{_libdir}/*.la
 mkdir -p $RPM_BUILD_ROOT/%{_datadir}/mythes
 
-%clean
-rm -rf $RPM_BUILD_ROOT
-
 %post -p /sbin/ldconfig
 
 %postun -p /sbin/ldconfig