(FACT-207) Remove all uses of :ldapname

Commit 1da7261da deprecated the use of :ldapname for facts; this commit
removes the use of :ldapname from the related facts and test coverage.
Merge pull request #604 from adrienthebo/maint/facter-2/fact-207-remove_ldapname_from_facts

(FACT-207) Remove all uses of :ldapname