Fixed bug: Inconsistent data state for instance attribute on failed save! attempt.

lib/sequencer/unit/import/common/model/save.rb

@@ -9,6 +9,7 @@ class Sequencer
             include ::Sequencer::Unit::Import::Common::Model::Mixin::HandleFailure
 
             uses :instance, :dry_run
+            provides :instance
 
             def process
               return if dry_run
@@ -16,6 +17,9 @@ class Sequencer
               instance.save!
             rescue => e
               handle_failure(e)
+
+              # unset instance if something went wrong
+              state.provide(:instance, nil)
             end
           end
         end