pgsql: Restore fullname[] contents before falling through in pg_open_tz

Restore fullname[] contents before falling through in pg_open_tzfile().

Fix oversight in commit af2c5aa88: if the shortcut open() doesn't work,
we need to reset fullname[] to be just the name of the toplevel tzdata
directory before we fall through into the pre-existing code. This failed
to be exposed in my (tgl's) testing because the fall-through path is
actually never taken under normal circumstances.

David Rowley, per report from Amit Kapila

Discussion: https://postgr.es/m/CAA4eK1LC7CaNhRAQ__C3ht1JVrPzaAXXhEJRnR5L6bfYHiLmWw@mail.gmail.com

Branch
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REL9_2_STABLE

Details
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https://git.postgresql.org/pg/commitdiff/9061680f06b06588281bdc8e59106eb33726360f

Modified Files
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src/timezone/pgtz.c | 1 +
1 file changed, 1 insertion(+)