pgsql: Don't raise "identifier will be truncated" messages in dblink

Don't raise "identifier will be truncated" messages in dblink
except creating new connections.

Branch
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REL8_1_STABLE

Details
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http://git.postgresql.org/gitweb?p=postgresql.git;a=commitdiff;h=268da2921907e7b5b1e9b0990957181a8dd7b410

Modified Files
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contrib/dblink/dblink.c |    4 ++--
1 files changed, 2 insertions(+), 2 deletions(-)