xmllint --format database.xml
xmllint --format info.xml
DB: Remove dbprefix from index names

Removed *dbprefix* prefix from index names in the database XML
description.

OC6 is stricter in parsing the database.xml file: index name has to be [a-zA-Z0-9_].

See issue #14
Merge pull request #16 from owncloud/db_idx_name_fix

Db idx name fix