Removed useless getChangeNumber() and setChangeNumber methods from *Operation interfaces.
These methods are useless because setChangeNumber() is never set inside production code, so changeNumber is always equal to -1 for all the update operations. In addition it is very unlikely the ChangeNumberIndexer could have computed the changeNumber before a results are sent to a persistent search.


AddOperation*.java, DeleteOperation*.java, ModifyDNOperation*.java, ModifyOperation*.java:
Removed changeNumber fields + getters and setters.
Code cleanup.

PersistentSearch.java:
In process*() public methods, removed the long changeNumber attributes.
Removed baseDN, scope and filter fields, and retrieve them directly from the SearchOperation.
Extracted methods isInScope(), isInScopeForModify(), isAnyInScopeForModify(), matchesFilter(), anyMatchesFilter(), sendEntry(), createControls().
to factorize duplicated code.

LocalBackend*Operation.java:
Consequence of the changes to PersistentSearch.process*() methods.
Code cleanup.

ECLServerWriter.java:
In publish(), consequence of the change to PersistentSearch.processAdd().
In doIt(), simplified code by extracting takeECLUpdate() method.