pgsql: Don't choke on files that are removed while pg_rewind runs.

Don't choke on files that are removed while pg_rewind runs.

If a file is removed from the source server, while pg_rewind is running, the
invocation of pg_read_binary_file() will fail. Use the just-added missing_ok
option to that function, to have it return NULL instead, and handle that
gracefully. And similarly for pg_ls_dir and pg_stat_file.

Reported by Fujii Masao, fix by Michael Paquier.

Branch
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master

Details
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http://git.postgresql.org/pg/commitdiff/b36805f3c54fe0e50e58bb9e6dad66daca46fbf6

Modified Files
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src/bin/pg_rewind/libpq_fetch.c |   37 ++++++++++++++++++++++++++++++-------
1 file changed, 30 insertions(+), 7 deletions(-)