npgsql - Npgsql2: Fixes for SQL generation bugs reported in #1010863 and

Log Message:
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Fixes for SQL generation bugs reported in #1010863 and #1010860

Modified Files:
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Npgsql2/src/Npgsql/SqlGenerators:
SqlBaseGenerator.cs (r1.28 -> r1.29)
(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/npgsql/Npgsql2/src/Npgsql/SqlGenerators/SqlBaseGenerator.cs?r1=1.28&r2=1.29)
VisitedExpression.cs (r1.17 -> r1.18)
(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/npgsql/Npgsql2/src/Npgsql/SqlGenerators/VisitedExpression.cs?r1=1.17&r2=1.18)