Older versions of SQLite don't like IF NOT EXISTS in virtual tables

synapse/storage/schema/delta/25/fts.py

@@ -38,7 +38,7 @@ CREATE INDEX event_search_ev_ridx ON event_search(room_id);
 
 
 SQLITE_TABLE = (
-    "CREATE VIRTUAL TABLE IF NOT EXISTS event_search"
+    "CREATE VIRTUAL TABLE event_search"
     " USING fts4 ( event_id, room_id, sender, key, value )"
 )