R1:2432a479976c

Reduce invasiveness of `bin/auth ldap`

Summary: The once-choppy LDAP waters seem to have calmed down a bit. Use the service profile log to get a pretty good idea of what's going on with LDAP (see D6391) instead of invasive logging to get a slightly better idea.

Test Plan:
$ ~/src/php-src/sapi/cli/php -f ./bin/auth ldap --trace
>>> [2] <connect> phabricator2_auth
<<< [2] <connect> 1,755 us
>>> [3] <query> SELECT * FROM `auth_providerconfig` ORDER BY id DESC
<<< [3] <query> 423 us
Enter LDAP…