pgsql: Fix errorhandling for reading from a pipe

Fix errorhandling for reading from a pipe

When reading a line from a pipe failed on no data being read, the
errorhandling was erroneously logging with %m even thoug no error
description is available for %m to print.  This flaw accidentally
introduced in 5c7038d70bb.

Reported-by: Peter Eisentraut <[email protected]>
Discussion: https://postgr.es/m/[email protected]

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/be41a9b0380778a07386208afbf3f41ba7286cf3

Modified Files
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src/common/exec.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)