CBQE-0: transfer.conversionusetransfer.ConversionUseTransfer.convert_sqlite_to_couchstore: Increase timeout to persist data on disk.

Change-Id: I92c1dc4150470fd2ca5d4c6b943aafbff9970c91
Reviewed-on: http://review.couchbase.org/31345
Reviewed-by: Sangharsh Agarwal <sangharsh.agarwal@globallogic.com>
Tested-by: Sangharsh Agarwal <sangharsh.agarwal@globallogic.com>