fix ldap-utils pkg install on rhel
fix db4 pkg install on redhat
fix user/group ownership for redhat platform
minor cleanup
Reordered logic in server.rb configuration and made default behavior to
create the config using slapd-config(5), not slapd.conf(5).
Removed old Debian specific code that assumes OpenLDAP is version 2.3 or
earlier.  (The last Debian release, etch, was end of lifed in 2010.).
Refactored code to install db-util packages to work on modern
installations on Ubuntu and Debian.