snmpctl. Separate copies of ber.[ch] have existed and been maintained in sync
in ldap, ldapd, ypldap and snmpd.
This commit moves the BER API into /usr/lib/libutil. All current consumers
already link libutil. ldapd and snmpd regress passes, and release builds.
With help from tb@ and guenther@.
ok deraadt@, tb@