SuSEFirewall: Reading SuSEfirewall2 configuration whenever it's possible

- Used not to work in inst-sys, but at the end of installation,
  package is already installed and we can actually read the config
- bnc#887406
Changes and version
Merge pull request #281 from kobliha/export-at-the-end-of-installation

SuSEFirewall: Reading SuSEfirewall2 configuration whenever it's possible