LU-1378 fid: Add console info for super seq allocation

LU-1378 fid: Add console info for super seq allocation

Add console information for super sequence allocation. Because
one super sequence will include 1 billion sequences, it rarely
happens in reality, so it will not cause the flood of console
msg.

Signed-off-by: Di Wang <di.wang@whamcloud.com>
Change-Id: I5154ee2a03006680b6a08d588287bf3941149457
Reviewed-on: http://review.whamcloud.com/2701
Tested-by: Hudson
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Tested-by: Maloo <whamcloud.maloo@gmail.com>
Reviewed-by: Fan Yong <yong.fan@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>