[test] Skip LDAP tests if any of the underlying programs is not found
Some programs are in ldap-utils or ldapscripts, which may not be installed
despite slapd may.
Follow-up on 282880f81311.
include *.pyinclude */*.pyrecursive-include data *.gif *.png *.ico *.css *.jsrecursive-include i18n *.porecursive-include wdoc *