Fix a bug when reporting errors claiming candidates

The SQL args were the wrong way around, so we tried to set error to the id.
Thankfully this failed as the id queried is not a valid uuid.

Fix by making args named like every other usage of query()

cutter/cutter/main.py

@@ -185,9 +185,9 @@ class Cutter(object):
 						# Any successful claim will clear its error.
 						result = query(self.conn, """
 							UPDATE events
-							SET error = %s
-							WHERE id = %s AND state = 'EDITED' AND error IS NULL
-						""", candidate.id, error)
+							SET error = %(error)s
+							WHERE id = %(id)s AND state = 'EDITED' AND error IS NULL
+						""", id=candidate.id, error=error)
 					except Exception:
 						self.logger.exception("Failed to set error for candidate {}, ignoring".format(format_job(candidate)))
 						self.refresh_conn()