use different sub-directories for databases of different indexing engines
rename the indexing directory from ".poindex-PROJECT-LANGUAGE" to ".translation_index"
note for UPGRADING: you have to remove old indexing directories manually
these changes are meant to ease migrations from one indexing engine to another and to
allow different indexing engines to be on the same server
git-svn-id: http://translate.svn.sourceforge.net/svnroot/translate/src/trunk/Pootle@7569 54714841-351b-0410-a198-e36a94b762f5