Fixes LdifReader related tests

The LdifReader tests were not passing when they were brough over from
Spring LDAP due to the fact that they depended on old conventions for
Spring Batch.  This wasn't found until someone logged a bug because not
all tests are executed with every build.  These tests should now pass.
Conditionally add custom scopes when using XML configuration

When using a combination of Java configuration and the XML namespace
configuration, prior to this commit, we would add the batch custom
scopes twice which lead to issues.  This commit gives priority to the
custom scopes provided by the java configuration.  If you've used
@EnableBatchProcessing and have configured batch components using the
batch namespace, the custom scopes that come with the java config will
take precidence.

This commit addresses Jira BATCH-2266