[Bug] FE failed to load image when doing checkpoint or restart.

[morningman]

Describe the bug
Error in fe.out

java.io.IOException: Read transaction states failed
        at org.apache.doris.transaction.GlobalTransactionMgr.readFields(GlobalTransactionMgr.java:371)
        at org.apache.doris.catalog.Catalog.loadTransactionState(Catalog.java:1798)
        at org.apache.doris.catalog.Catalog.loadImage(Catalog.java:1436)
        at org.apache.doris.master.Checkpoint.runAfterCatalogReady(Checkpoint.java:100)
        at org.apache.doris.common.util.MasterDaemon.runOneCycle(MasterDaemon.java:58)
        at org.apache.doris.common.util.Daemon.run(Daemon.java:116)
Caused by: org.apache.doris.common.AnalysisException: errCode = 2, detailMessage = databaseTransactionMgr[14981] does not exist
        at org.apache.doris.transaction.GlobalTransactionMgr.getDatabaseTransactionMgr(GlobalTransactionMgr.java:76)
        at org.apache.doris.transaction.GlobalTransactionMgr.readFields(GlobalTransactionMgr.java:367)
        ... 5 more

To Reproduce

1. create database and table
2. do some load
3. drop the db
4. make a checkpoint meta image
5. start fe from this image, failed

Introduced by #3369