Don't crash when failing to update note_search DB.

scripts/generate.py

@@ -108,7 +108,13 @@ def load_all(top_dir_relative):
 def regen_all(src_top, dest_top, *, docs=None, db=None):
     files_generated = 0
     cur = db.cursor()
+    cleaned_db = False
+
+    try:
         cur.execute('DELETE FROM note_search;')
+        cleaned_db = True
+    except sqlite3.OperationalError as err:
+        logging.warn("Error pre-cleaning DB, search won't be updated")
 
     docs = load_all(src_top)
     doc_to_headline_remapping = {}