Migration during shutdown can cause AE

 INFO [FlushWriter:1] 2013-02-08 17:03:49,727 Memtable.java (line 453) Writing Memtable-schema_columns@1757448463(793/793 serialized/live bytes, 15 ops)
 INFO [FlushWriter:1] 2013-02-08 17:03:49,752 Memtable.java (line 487) Completed flushing /tmp/dtest-gEW6x2/test/node3/data/system/schema_columns/system-schema_columns-ib-4-Data.db (339 bytes) for commitlog position ReplayPosition(segmentId=1360364624598, position=66887)
 INFO [CompactionExecutor:2] 2013-02-08 17:03:49,754 CompactionTask.java (line 112) Compacting [SSTableReader(path='/tmp/dtest-gEW6x2/test/node3/data/system/schema_columns/system-schema_columns-ib-4-Data.db'), SSTableReader(path='/tmp/dtest-gEW6x2/test/node3/data/system/schema_columns/system-schema_columns-ib-3-Data.db'), SSTableReader(path='/tmp/dtest-gEW6x2/test/node3/data/system/schema_columns/system-schema_columns-ib-2-Data.db'), SSTableReader(path='/tmp/dtest-gEW6x2/test/node3/data/system/schema_columns/system-schema_columns-ib-1-Data.db')]
 INFO [CompactionExecutor:3] 2013-02-08 17:03:49,759 CompactionTask.java (line 272) Compacted 4 sstables to [/tmp/dtest-gEW6x2/test/node3/data/system/schema_columnfamilies/system-schema_columnfamilies-ib-5,].  7,473 bytes to 5,595 (~74% of original) in 32ms = 0.166744MB/s.  6 total rows, 4 unique.  Row merge counts were {1:3, 2:0, 3:1, 4:0, }
ERROR [InternalResponseStage:1] 2013-02-08 17:03:49,787 CassandraDaemon.java (line 135) Exception in thread Thread[InternalResponseStage:1,5,main]
java.lang.AssertionError
    at org.apache.cassandra.service.MigrationManager.passiveAnnounce(MigrationManager.java:320)
    at org.apache.cassandra.config.Schema.updateVersionAndAnnounce(Schema.java:458)
    at org.apache.cassandra.db.DefsTable.mergeSchema(DefsTable.java:347)
    at org.apache.cassandra.service.MigrationTask$1.response(MigrationTask.java:66)
    at org.apache.cassandra.net.ResponseVerbHandler.doVerb(ResponseVerbHandler.java:47)
    at org.apache.cassandra.net.MessageDeliveryTask.run(MessageDeliveryTask.java:56)
    at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
    at java.lang.Thread.run(Thread.java:662)