erp5_curation_request: Use less deceptive variable name for curation request line

bt5/erp5_curation_request/SkinTemplateItem/portal_skins/erp5_curation_request/CurationRequest_init.py

 curation_record = context.curation_record_module.newContent(portal_type='Curation Record')
-curation_record_line = context.newContent(portal_type='Curation Request Line',
+curation_request_line = context.newContent(portal_type='Curation Request Line',
                                           aggregate_value=curation_record,
                                           quantity=1)
 # set reference
-curation_record_line.Object_getIncrementalReference(generator_id_group='curation_request_line_reference')
+curation_request_line.Object_getIncrementalReference(generator_id_group='curation_request_line_reference')

bt5/erp5_curation_request/SkinTemplateItem/portal_skins/erp5_curation_request/CurationRequest_newCurationRequestForUrl.py

 if context.getAggregateRelatedValue() is None:
   curation_request = context.curation_request_module.newContent(portal_type='Curation Request')
-  curation_record_line = curation_request.newContent(portal_type='Curation Request Line',
+  curation_request_line = curation_request.newContent(portal_type='Curation Request Line',
                                                      aggregate_value=context)
   context.submit()