[SIGNED-OFF] Bug 15113: koha-rebuild-zebra should check USE_INDEXER_DAEMON and skip...

[SIGNED-OFF] Bug 15113: koha-rebuild-zebra should check USE_INDEXER_DAEMON and skip if enabled

This patch changes the behaviour of the koha-rebuild-zebra script in the following way:

USE_INDEXER_DAEMON=no
- Keeps the current behaviour

USE_INDEXER_DAEMON=yes
- It skips incremental indexing to avoid races.

Caveats:
- A --force option is introduced for useing in a specific situtation that might need it
 (i.e. the administrator knows what he's doing).
- If --full is passed, the reindexing is not skipped.

The documentation files and messages are adjusted accordingly.

This patch should help users that want to use the indexing daemon, in which case they wouldn't need
to change their default 5 min cronjob (it will be just skipped). Ultimately, koha-common could have
USE_INDEXER_DAEMON = yes by default, but that's subject for another bug report.

To test:
- Play with the different option switches and USE_INDEXER_DAEMON
- Things work as expected
- Sign off

Regards

Signed-off-by: Hector Castro <hector.hecaxmmx@gmail.com>
Works as expected

Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>

Signed-off-by: Your Full Name <your_email>