fwmod:
 * avoid any Freetz related modifications in STEP 3 if STEP 2 has not been carried out
 * this makes it possible to use fwmod as pure "unpack/pack image"-tool
 * refs [http://freetz.org/wiki/help/howtos/development/repack_fw this howto]


git-svn-id: file:///var/svn/freetz/trunk@12055 149334a1-2f27-0410-a3b9-fc62619ac1e6