Allow lucene to be turned off on startup. This would be helpful when another program is doing indexing (e.g. solr). Right now, it's finnicky.
The situation for one client:
Solr is implemented so lucene indexing is not in use. However, this is the current functionality:
1. Liferay starts up
2. Liferay reads lucene properties and populates data/lucene folder.
3. Solr plugin is then deployed.
4. Solr then overwrites a number of portal.properties and ignores the lucene folder.
Liferay shouldn't have to read the lucene properties and populate the indexes if lucene is not going to be used.