pgsql: Update timezone mapping for Windows with new timezones added in

Log Message:
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Update timezone mapping for Windows with new timezones added
in windows servicepacks.
Fix timezone mapping for "Mexico 2"

Tags:
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REL8_2_STABLE

Modified Files:
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pgsql/src/timezone:
pgtz.c (r1.48 -> r1.48.2.1)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/timezone/pgtz.c?r1=1.48&r2=1.48.2.1)