dataMgr:whImporter: fix appending wrong records.

1) Fix a bug that appendRecordsOnly() appended records that
   were earlier than the last record of data table.
2) Rename appendUpdateRecords() to updateRecordsFromFile().

regression: exit on meeting unknown strategy.

Exit regression execution while meeting unknown strategy.

Signed-off-by: Zhengwang Ruan <ruan.zhengwang@gmail.com>