migration25+migration26: add verbose error log

[yyforyongyu]

trafficstars

Fixing a user reported error re migration25,

2022-07-21 15:59:59.362 [INF] CHDB: Checking for schema update: latest_version=27, db_version=24
2022-07-21 15:59:59.362 [INF] CHDB: Performing database schema migration
2022-07-21 15:59:59.362 [INF] CHDB: Applying migration #25
2022-07-21 15:59:59.462 [INF] CHDB: Unable to apply migration #25
2022-07-21 15:59:59.685 [ERR] LTND: unable to open graph DB: unable to fetch chan info: no chan info found
2022-07-21 15:59:59.685 [ERR] LTND: Shutting down because error in main method: unable to open databases: unable to open graph DB: unable to fetch chan info: no chan info found
2022-07-21 15:59:59.686 [INF] LTND: Shutdown complete

[yyforyongyu]

Closed as the reported issue has been fixed.