pgsql: Move fsync routines of initdb into src/common/

Move fsync routines of initdb into src/common/

The intention is to used those in other utilities such as pg_basebackup
and pg_receivexlog.

From: Michael Paquier <michael.paquier@gmail.com>

Branch
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master

Details
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http://git.postgresql.org/pg/commitdiff/bf5bb2e85b6492c7245b9446efaf43d52a98db13

Modified Files
--------------
src/bin/initdb/initdb.c         | 270 ++-------------------------------------
src/bin/initdb/nls.mk           |   2 +-
src/bin/pg_basebackup/nls.mk    |   2 +-
src/common/Makefile             |   2 +-
src/common/file_utils.c         | 276 ++++++++++++++++++++++++++++++++++++++++
src/include/common/file_utils.h |  22 ++++
src/tools/msvc/Mkvcbuild.pm     |   2 +-
7 files changed, 313 insertions(+), 263 deletions(-)