pgsql: Fix bogus logic for zic -P option.

Fix bogus logic for zic -P option.

The quick hack I added to zic to dump out currently-in-use timezone
abbreviations turns out to have a nasty bug: within each zone, it was
printing the last "struct ttinfo" to be *defined*, not necessarily the
last one in use.  This was mainly a problem in zones that had changed the
meaning of their zone abbreviation (to another GMT offset value) and later
changed it back.

As a result of this error, we'd missed out updating the tznames/ files
for some jurisdictions that have changed their zone abbreviations since
the tznames/ files were originally created.  I'll address the missing data
updates in a separate commit.

Branch
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REL9_4_STABLE

Details
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http://git.postgresql.org/pg/commitdiff/03163139c9553c6ee4c26a73e21aaef5da22be45

Modified Files
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src/timezone/zic.c |   33 ++++++++++++++++++---------------
1 file changed, 18 insertions(+), 15 deletions(-)