Обсуждение: pgsql: Fix concat_ws() to not insert a separator after leading NULL arg

Fix concat_ws() to not insert a separator after leading NULL argument(s).

Per bug #6181 from Itagaki Takahiro.  Also do some marginal code cleanup
and improve error handling.

Branch
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REL9_1_STABLE

Details
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http://git.postgresql.org/pg/commitdiff/579577320ef449442f804043a67ce5c13d679679

Modified Files
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src/backend/utils/adt/varlena.c |   34 +++++++++++++++++++++++-----------
1 files changed, 23 insertions(+), 11 deletions(-)