[Review] Request from 'schubi2' @ 'yast/yast-network/review_141001_autoyast_do_not_overwrite_firewall_settings'

Please review the following changes:
  * efc4dc8 typo
  * 0f78165 added testcase
  * 1b545dd Revert "adapt Rakefile to submit to correct build service project in maintenance branch SLE-12-GA"
  * 0e4e651 adapt Rakefile to submit to correct build service project in maintenance branch SLE-12-GA
  * a56e86a removed not needed import
  * f8bc950 moved autoyast stuff into lan_auto.rb
  * 03880f6 packaging
  * c441ccf Autoyast: Do not overwrite in autoinst.xml file configured firewall settings by installed firewall settings if the installed network is kept.

You don't need to explicitly name optional parameters in ruby when calling the method. ```Lan.Read(:cache, false)``` would work without the side effect of assigning a variable called ```read_firewall_settings``` in lan_auto.