pgsql: Don't include unused space in LOG_NEWPAGE records.

Don't include unused space in LOG_NEWPAGE records.

This is the same trick we use when taking a full page image of a buffer
passed to XLogInsert.

Branch
------
master

Details
-------
http://git.postgresql.org/pg/commitdiff/9e857436ef7dff8fb8a0bf43cfe62650e2be6be9

Modified Files
--------------
src/backend/access/gin/gininsert.c    |    4 +-
src/backend/access/gist/gist.c        |    2 +-
src/backend/access/heap/heapam.c      |  123 ++++++++++++++++++++++-----------
src/backend/access/heap/rewriteheap.c |    6 +-
src/backend/access/nbtree/nbtree.c    |    2 +-
src/backend/access/nbtree/nbtsort.c   |    2 +-
src/backend/access/spgist/spginsert.c |    6 +-
src/backend/commands/tablecmds.c      |    8 ++-
src/backend/commands/vacuumlazy.c     |    6 +-
src/include/access/heapam_xlog.h      |   10 +--
src/include/access/xlog_internal.h    |    2 +-
11 files changed, 109 insertions(+), 62 deletions(-)