The LDAP client configuration part now contains help for users that can not
log in because of a missing shell. When shells like bash are on different
paths (/bin/bash vs. /usr/local/bin/bash), entries need to be created in
/etc/shells and proper symlinks set to make this work.

Reviewed by: wblock
Approved by: wblock
Committed at: Essen FreeBSD Hackathon
Differential Revision: https://reviews.freebsd.org/D3194