pgsql: Move log_newpage and log_newpage_buffer to xlog.c.

Move log_newpage and log_newpage_buffer to xlog.c.

log_newpage is used by many indexams, in addition to heap, but for
historical reasons it's always been part of the heapam rmgr. Starting with
9.3, we have another WAL record type for logging an image of a page,
XLOG_FPI. Simplify things by moving log_newpage and log_newpage_buffer to
xlog.c, and switch to using the XLOG_FPI record type.

Bump the WAL version number because the code to replay the old HEAP_NEWPAGE
records is removed.

Branch
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master

Details
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http://git.postgresql.org/pg/commitdiff/54685338e37889eebd473804c3feb006dd83a882

Modified Files
--------------
src/backend/access/gin/gindatapage.c     |    1 -
src/backend/access/gin/gininsert.c       |    1 -
src/backend/access/gin/ginxlog.c         |    3 +-
src/backend/access/gist/gist.c           |    1 -
src/backend/access/heap/heapam.c         |  180 ------------------------------
src/backend/access/nbtree/nbtree.c       |    1 -
src/backend/access/nbtree/nbtsort.c      |    1 -
src/backend/access/rmgrdesc/heapdesc.c   |    9 --
src/backend/access/spgist/spginsert.c    |    1 -
src/backend/access/transam/xlog.c        |  131 +++++++++++++++++++++-
src/backend/commands/tablecmds.c         |    1 -
src/backend/replication/logical/decode.c |    8 --
src/include/access/heapam_xlog.h         |   19 +---
src/include/access/xlog.h                |    5 +
src/include/access/xlog_internal.h       |    2 +-
15 files changed, 139 insertions(+), 225 deletions(-)