dns/dnstable: upgrade to version 1.2.0

dnstable 1.2.0:

  * Implement indexing using RRtypes for ENTRY_TYPE_RRSET_NAME_FWD and
    ENTRY_TYPE_RDATA_NAME_REV entries. This uses RFC6840 RRtype bitmaps
    as the primary data structure.

  * Added support for dnstable entries encoding version information and
    time metadata.

  * The version entries, time metadata, and rrtype index information are
    generated by an updated dnstable-convert. Files generated by the old
    dnstable-convert will be processed as they were with the previous
    dnstable versions i.e., the new entry types and rrset index
    information will be absent.

  * Add -R flag to dnstable_dump and dnstable_lookup to add raw rdata
    representation to outputs.

  * Add long options to dnstable_dump to fix bug in not accepting some
    options properly.

  * Fix dnstable_lookup usage output.

  * Refactor time formatters and fix compiler warnings.

  * Ignore entries which fail decoding for use with legacy empty data.

  * Miscellaneous documentation improvements.

Sponsored by:	Farsight Security, Inc.