Replay update replica failed when table has been dropped

[EmmyMiao87]

Describe the bug

2021-04-21 16:40:13,930 INFO (stateListener|86) [EditLog.loadJournal():177] Begin to unprotect create table. db = default_cluster:kadm table = 3106512
2021-04-21 16:40:14,022 INFO (stateListener|86) [SchemaChangeJobV2.replayPending():709] replay pending schema change job: 3112634, table id: 3106512
2021-04-21 16:40:14,080 INFO (stateListener|86) [SchemaChangeJobV2.replayWaitingTxn():738] replay waiting txn schema change job: 3112634, table id: 3106512
2021-04-21 16:40:14,097 INFO (stateListener|86) [EditLog.loadJournal():196] Begin to unprotect drop table. db = default_cluster:kadm table = 3106512
2021-04-21 16:40:14,098 INFO (stateListener|86) [CatalogRecycleBin.recycleTable():104] recycle table[3106512-kadm_waybill_detail_describething]
2021-04-21 16:40:14,098 INFO (stateListener|86) [Catalog.unprotectDropTable():4465] finished dropping table[kadm_waybill_detail_describething] in db[default_cluster:kadm]
2021-04-21 16:40:14,098 WARN (stateListener|86) [Catalog.replayUpdateReplica():4549] olap table is null when update repica, table id: 3106512 partition id: 3106487 index id: 3112635 index id: 3112635 tablet id: 3115544 backend id: 12003 replica id: 3115545 version: 1 version hash: 0 schema hash: -1 data size: 0 row count: 0 last failed version: -1 last failed version hash: 0 last success version: 1 last success version hash: 0
2021-04-21 16:40:14,098 ERROR (stateListener|86) [EditLog.loadJournal():808] Operation Type 45
java.lang.NullPointerException: null
at org.apache.doris.catalog.Catalog.replayUpdateReplica(Catalog.java:4551) ~[palo-fe.jar:3.4.0]
at org.apache.doris.persist.EditLog.loadJournal(EditLog.java:408) [palo-fe.jar:3.4.0]
at org.apache.doris.catalog.Catalog.replayJournal(Catalog.java:2482) [palo-fe.jar:3.4.0]
at org.apache.doris.catalog.Catalog.transferToMaster(Catalog.java:1180) [palo-fe.jar:3.4.0]
at org.apache.doris.catalog.Catalog.access$1100(Catalog.java:270) [palo-fe.jar:3.4.0]
at org.apache.doris.catalog.Catalog$4.runOneCycle(Catalog.java:2399) [palo-fe.jar:3.4.0]
at org.apache.doris.common.util.Daemon.run(Daemon.java:116) [palo-fe.jar:3.4.0]

To Reproduce
Steps to reproduce the behavior:
Version 0.14.7

1. create table
2. schema change
3. drop table before schema change finished
4. restart fe
5. failed to start fe

Expected behavior
Tables that no longer exist should no longer be modified.