pgsql: Update time zone abbreviation lists for changes missed since 200

Update time zone abbreviation lists for changes missed since 2006.

Most (all?) of Russia has moved to what's effectively year-round daylight
savings time, so that the "standard" zone names now mean an hour later
than they used to. Update that, notably changing MSK as per recent
complaint from Sergey Konoplev, but also CHOT, GET, IRKT, KGT, KRAT,
MAGT, NOVT, OMST, VLAT, YAKT, YEKT. The corresponding DST abbreviations
are presumably now obsolete, but I left them in place with their old
definitions, just to reduce any possible breakage from this change.

Also add VOLT (Europe/Volgograd), which for some reason we never had
before, as well as MIST (Antarctica/Macquarie), and fix obsolete
definitions of MAWT, TKT, and WST.

Branch
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REL9_1_STABLE

Details
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http://git.postgresql.org/pg/commitdiff/f1bd8a82d7bc127d752e22689ebed9632555cc28

Modified Files
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src/timezone/tznames/Antarctica.txt | 4 ++-
src/timezone/tznames/Asia.txt | 46 +++++++++++++++---------------
src/timezone/tznames/Default | 52 ++++++++++++++++++-----------------
src/timezone/tznames/Europe.txt | 8 +++--
src/timezone/tznames/Pacific.txt | 6 +++-
5 files changed, 62 insertions(+), 54 deletions(-)