[test/ldap] have RQL2LDAPFilterTC use its own database
I do not know what RQL2LDAPFilterTC is about and why it does this strange reuse
of LDAPUserSourceTC pre_setup_database but it is certainly a good idea to have it
use a dedicated database-cache.
debian/tmp/usr/lib/PY_VERSION/site-packages/cubicweb/web usr/lib/PY_VERSION/site-packages/cubicweb
debian/tmp/usr/share/cubicweb/cubes/shared/data usr/share/cubicweb/cubes/shared
debian/tmp/usr/share/cubicweb/cubes/shared/wdoc usr/share/cubicweb/cubes/shared