pgsql: Fix pg_receivexlog --synchronous

Fix pg_receivexlog --synchronous

Make pg_receivexlog work correctly with --synchronous without slots

Backpatch to 9.5

Gabriele Bartolini, reviewed by Michael Paquier and Simon Riggs

Branch
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master

Details
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http://git.postgresql.org/pg/commitdiff/49340627f9821e447f135455d942f7d5e96cae6d

Modified Files
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src/bin/pg_basebackup/receivelog.c | 28 +++++++++++++++-------------
1 file changed, 15 insertions(+), 13 deletions(-)