anonymization: fix orders with patron_pid

* fixes an error when anonymizing an order that does not have the
  patron_pid in the order lines

invenio_app_ils/patrons/anonymization.py

@@ -172,7 +172,7 @@ def anonymize_patron_data(patron_pid, force=False):
     for hit in patron_acquisitions:
         acquisition = Order.get_record_by_pid(hit.pid)
         for line in acquisition["order_lines"]:
-            if line["patron_pid"] == patron_pid:
+            if line.get("patron_pid") == patron_pid:
                 line["patron_pid"] = anonymous_patron_fields["pid"]
         acquisition.commit()
         current_ils_acq.order_indexer.index(acquisition)

tests/data/acq_orders.json

@@ -85,5 +85,26 @@
     "pid": "acqoid-6",
     "status": "ORDERED",
     "provider_pid": "acq-provid-2"
+  },
+  {
+    "order_date": "2020-01-29",
+    "order_lines": [
+      {
+        "copies_ordered": 1,
+        "document_pid": "docid-1",
+        "medium": "hardcover",
+        "recipient": "patron",
+        "patron_pid": "4"
+      },
+      {
+        "copies_ordered": 1,
+        "document_pid": "docid-1",
+        "medium": "hardcover",
+        "recipient": "patron"
+      }
+    ],
+    "pid": "acqoid-7",
+    "status": "RECEIVED",
+    "provider_pid": "acq-provid-2"
   }
 ]