pgsql: Fix pg_xlogdump's calculation of full-page image data.

Fix pg_xlogdump's calculation of full-page image data.

The old formula was completely bogus with the new WAL record format.

Branch
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master

Details
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http://git.postgresql.org/pg/commitdiff/ebc2b681b8ffa597137aa7a19619e6a21176e928

Modified Files
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contrib/pg_xlogdump/pg_xlogdump.c |   21 ++++++++++++++++++---
1 file changed, 18 insertions(+), 3 deletions(-)