add indices for all backends that support them; clenup

tests/data/slapd-acl.conf

tests/data/slapd-cache-master.conf

tests/data/slapd-chain1.conf

tests/data/slapd-chain2.conf

tests/data/slapd-component.conf

tests/data/slapd-dn.conf

tests/data/slapd-glue-syncrepl1.conf

tests/data/slapd-glue-syncrepl2.conf

tests/data/slapd-glue.conf

tests/data/slapd-idassert.conf

tests/data/slapd-ldapglue.conf

tests/data/slapd-ldapgluegroups.conf

tests/data/slapd-ldapgluepeople.conf

tests/data/slapd-limits.conf

tests/data/slapd-master.conf

tests/data/slapd-meta2.conf

tests/data/slapd-ppolicy.conf

tests/data/slapd-proxycache.conf

tests/data/slapd-pw.conf

tests/data/slapd-ref-slave.conf