Fix edge case where input is being checked against edge case.

Added greater than equals sign for an edge case.
migration: allow built-in copy function instead of calling an external command.

The cost for calling an external copy command caused a poor performance
when copying many small files.

Now use a built-in copy function by default, unless the config file
explicitely specify the "action_cmd" parameter.
Updated Licence from CeCILL to CeCILL-C: as with LGPL, Robinhood can be integrated to commercial products.
Removed old spec files (for RHEL4).
Doc update from 2.4.3.
ListMgr and EntryProcessor: DB request batching.

The goal of this change is to perform batch request in the DB
of the form 'INSERT INTO table VALUES (values1),(values2),...'
This promizes better performance as the DB operation
requires a single locking for the batch request
and a single sync to disk to COMMIT the transaction.

The patch first consists in implementing ListMgr_BatchInsert()
that is also used for update, by adding 'ON DUPLICATE KEY...' to the statement.
By the way, static set for 'ON DUPLICATE KEY UPDATE' on NAMES table
has been made dynamic. It is now built using attrset2updatelist() with an extra argument.

The other part of the patch consists in batching (in the entry processor)
the consecutive pending DB requests that do the same DB operation type
with the same attribute mask.
This suppose no change is done to the op_type or the attribute mask
in the batched step (db_apply). So such modifications have been
moved to a separate step (pre_apply) that is mandatory
before going to db_apply.
DB_APPLY step is split into 2 stage functions: db_apply and db_batch_apply,
one is called for single DB ops, the other for batches.
The function dbop_is_batchable(op1, op2) determines if 2 operations
can be batched together.
repository: autogen.sh installs git prepare-commit hook.

Add comments into git commit messages:
- template commit message format
- warnings about code syntax
- diff output
tests: fix tests 637 to 640 (missing purge policies in config file).

The tests failed because they are about purge triggers but no purge policy
was defined in the config files, so the purge was disabled.
Config: allow using environment variables in config file.

Example: fspath = $ROOT;
rbh-find: bulk DB search using -bulk (-b) option.

Restore the following feature from 2.4:
when no path is given to rbh-find and the -bulk option
is specified, the query is performed on the whole DB
with the speficied criteria (not recursive traversal or directories).