Remove hack for rusqlite optional()

Author: jyn514

database/src/pool/sqlite.rs

@@ -331,14 +331,8 @@ impl Connection for SqliteConnection {
                         cid.and_then(|cid| {
                             query
                                 .query_row(params![&sid, &cid.0], |row| row.get(0))
-                                .optional()
                                 .unwrap_or_else(|e| {
-                                    // work around https://github.com/rusqlite/rusqlite/issues/777
-                                    if let rusqlite::Error::InvalidColumnType(_, _, rusqlite::types::Type::Null) = e {
-                                        None
-                                    } else {
-                                        panic!("{:?}: series={:?}, aid={:?}", e, sid, cid);
-                                    }
+                                    panic!("{:?}: series={:?}, aid={:?}", e, sid, cid);
                                 })
                         })
                     })