pgsql: Improve reporting of error situations in find_other_exec().

pgsql: Improve reporting of error situations in find_other_exec().

Improve reporting of error situations in find_other_exec().

This function suppressed any stderr output from the called program, which
is unnecessary in the normal case and unhelpful in error cases.  It also
gave a rather opaque message along the lines of "fgets failure: Success"
in case the called program failed to return anything on stdout.  Since
we've seen multiple reports of people not understanding what's wrong when
pg_ctl reports this, improve the message.

Back-patch to all active branches.

Branch
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REL8_4_STABLE

Details
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http://git.postgresql.org/pg/commitdiff/2754cdc713a03ec038bbc98f50fe3a465c0e517c

Modified Files
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src/port/exec.c |   13 +++++++++++--
1 files changed, 11 insertions(+), 2 deletions(-)