ITS#3092: Rename sl_free() and friends to slap_sl_free()

servers/slapd/acl.c

servers/slapd/attr.c

servers/slapd/back-bdb/search.c

servers/slapd/bind.c

servers/slapd/ch_malloc.c

servers/slapd/connection.c

servers/slapd/dn.c

servers/slapd/filter.c

servers/slapd/ldapsync.c

servers/slapd/main.c

servers/slapd/operation.c

servers/slapd/proto-slap.h

servers/slapd/result.c

servers/slapd/sasl.c

servers/slapd/saslauthz.c

servers/slapd/schema_init.c

servers/slapd/schema_prep.c

servers/slapd/search.c

servers/slapd/sessionlog.c

servers/slapd/sl_malloc.c