Log Message:
-----------
Remove unused include file, per ITAGAKI Takahiro. AFAICT this has been
dead code since Postgres95.
Removed Files:
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pgsql/src/include/storage:
itempos.h
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/include/storage/itempos.h)