pgsql: pg_basebackup pg_receivexlog: Issue fsync more carefully

pg_basebackup pg_receivexlog: Issue fsync more carefully

Several places weren't careful about fsyncing in the way. See 1d4a0ab1
and 606e0f98 for details about required fsyncs.

This adds a couple of functions in src/common/ that have an equivalent
in the backend: durable_rename(), fsync_parent_path()

From: Michael Paquier <michael(dot)paquier(at)gmail(dot)com>

Branch
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master

Details
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http://git.postgresql.org/pg/commitdiff/bc34223bc1e2c51dff2007b3d3bd492a09b5a491

Modified Files
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src/bin/pg_basebackup/pg_basebackup.c | 27 +++++++++
src/bin/pg_basebackup/receivelog.c | 52 ++++++++++-------
src/common/file_utils.c | 105 ++++++++++++++++++++++++++++++++--
src/include/common/file_utils.h | 7 ++-
4 files changed, 162 insertions(+), 29 deletions(-)