npgsql - Npgsql2: Fixed previous patch as it breaks when using an

Log Message:
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Fixed previous patch as it breaks when using an internal NpgsqlCommand which receives only a Connector in its constructor as the CheckConformingStrings method does. This is caused by not having an NpgsqlConnection available when using this internal constructor. Now it uses the Connector object instead of NpgsqlConnection to get the compatibility version check.

Modified Files:
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Npgsql2/src/Npgsql:
NpgsqlDataReader.cs (r1.20 -> r1.21)
(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/npgsql/Npgsql2/src/Npgsql/NpgsqlDataReader.cs?r1=1.20&r2=1.21)