Read local users before writing them during autoinstallation

* Some package could add a new user during autoinstallation and
  we need to make sure that we don't clobber them.
* As Users module does not have a functionality to 'sync' data,
  we export, read and re-import data.

Rakefile

@@ -3,4 +3,5 @@ require "yast/rake"
 Yast::Tasks.configuration do |conf|
   #lets ignore license check for now
   conf.skip_license_check << /.*/
+  conf.obs_target = "SLE_12"
 end

src/clients/users_finish.rb

@@ -68,6 +68,15 @@ def main
 
         if Mode.autoinst
           # Write imported users (during autoupgrade no changes are done)
+
+          # During installation, some package could add a new user, so we
+          # need to read them again before writing.
+          Users.SetExportAll(true)
+          saved = Users.Export
+          Users.ReadLocal
+          Users.Import(saved)
+
+          # Write users
           Users.SetWriteOnly(true)
           @progress_orig = Progress.set(false)
           @ret = Users.Write == ""