plproxy - plproxy: Use server_encoding as remote connection encoding

Log Message:
-----------
Use server_encoding as remote connection encoding

Previous use of client_encoding was wrong, but seemed to work because
of binary i/o which bypassed the encoding checks.

Noticed and fixed by Hiroshi Saito

Modified Files:
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plproxy/src:
execute.c (r1.13 -> r1.14)
(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/plproxy/plproxy/src/execute.c.diff?r1=1.13&r2=1.14)