Remove unused result_new local in get_ruby_value_from_result_set

Running specs under `RUBYOPT=-w` (e.g. JRuby head CI) surfaced:

    lib/plsql/jdbc_connection.rb:381: warning: assigned but unused
    variable - result_new

The variable was assigned but never read; the method already returned
the converted value. Dropping the assignment silences the warning
without changing behavior.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: yahonda

lib/plsql/jdbc_connection.rb

@@ -378,7 +378,7 @@ def get_bind_variable(stmt, i, type)
     def get_ruby_value_from_result_set(rset, i, metadata)
       ruby_type = SQL_TYPE_TO_RUBY_CLASS[metadata[:sql_type]]
       ora_value = get_bind_variable(rset, i, ruby_type)
-      result_new = ora_value_to_ruby_value(ora_value)
+      ora_value_to_ruby_value(ora_value)
     end
 
     def result_set_to_ruby_data_type(column_type, column_type_name)