entry processor: optimization to batch more requests.

Previously, the criteria for batching DB operations was having the
same operation type (insert, update...) and the same attribute mask.
Actually, requests with different attribute masks can be batched
as long as the attribute mask for each table is the same (or 0).
Thus, this allows batching operations on directories and striped files,
as the directoy has no stripe information, but its attribute mask
is the same as files for other DB tables.

Change-Id: I6015b33aa3b72405b4ba3e46fc4fdc7752928b88
fs_scan/entry_proc: handle all cases of layout change in Lustre 2.4+

Since Lustre 2.4 <non-striped> to <striped> is not the only possible
change in file striping, as it can now been changed by swap_layouts, hsm_release...
With Lustre2.4, this patch detects stripe change based on layout_gen number.
This information is stored as the "validator" field in stripe_info table.
FS scan now systematically get file stripe info in Lustre 2.4+
as it is needed to check the layout_gen.

Added tests 117a-k and 118a-c to check most of the possibles cases
with FS scan, changelogs, and rbh-diff.

Change-Id: I348df7051f30b35f60a66e407c55262c4400779b
listmgr: manage conversion of stripe validator field.

STRIPE_INFO.validator field changes from 2.5.3 to 2.5.4.
Previously it was an "INT UNSIGNED" it is now just an "INT"
as it must handle special values like "-1" for empty layout
(unfortunately, "0" is a valid layout_gen number).

The conversion automatically runs when robinhood starts.
It takes about 10sec per million of files.

Change-Id: Ieb5ac48cbb421341c93fbd95e9dd4cc5fd2ab81f
The xattr library is necessary for Lustre, and is also
useful for other filesystems, so always build Robinhood with it.

Change-Id: I5d8cf528cd0b25c55c8ab87823375e5a9e496e42
listmgr: display an estimated time to convert a DB field.

Change-Id: I0147d8374cb5edcb9c67473f68f1f35d298c744c
release 2.5.4.

Change-Id: Ic58f28241907bc52312ac022baaf034d3474c1fb
tests: add lines of context in test output.

grep 5 lines before and 1 line after the error.

Change-Id: I7197bb71bc6a58205b1f179f4ae656b445839ada