Change config option examples to v3

Reference v3 in the config help text for the day when v2 is removed.

Change-Id: I4247b104d0490d264bbc36c3dad0c59f29c4345d
Remove unnecessary ldap import

Since ldap.filter is imported, there is no need to also import ldap.

Change-Id: I9e56a2d3d58c425b9655507263f7d453fab2c568
Merge "Change config option examples to v3"
Merge "Remove unnecessary ldap import"