hplsql should add enterGlobalScope func to UDF

code in Udf.java

    if (exec == null) {
      exec = new Exec();
      String query = queryOI.getPrimitiveJavaObject(arguments[0].get());
      String[] args = { "-e", query, "-trace" };
      try {
        exec.setUdfRun(true);
        exec.init(args);
      } catch (Exception e) {
        throw new HiveException(e.getMessage());
      }
    }
    if (arguments.length > 1) {
      setParameters(arguments);
    }
    Var result = exec.run();
    if (result != null) {
      return result.toString();
    }

Here is my thoughts

we should add 'exec.enterGlobalScope(); ' between 'exec = new Exec();' and 'setParameters(arguments);'
Because if we do not call exec.enterGlobalScope(), setParameters(arguments) will useless. Vars are not added into scope , but exec.run() will use vars which we set. The vars are parameters passed to UDF, [, :1, :2, ...n] which are description in Udf.java

Before add this function, the result as follow. we get the wrong result, because the result contains empty string

Starting pre-SQL statement
Starting pre-SQL statement
Starting pre-SQL statement
Starting pre-SQL statement
Starting pre-SQL statement
Starting query
Query executed successfully (2.30 sec)
Ln:8 SELECT completed successfully
Ln:8 Standalone SELECT executed: 1 columns in the result set
Hello, !
Hello, !

After add this function, we get the right result

Starting pre-SQL statement
Starting pre-SQL statement
Starting pre-SQL statement
Starting pre-SQL statement
Starting pre-SQL statement
Starting query
Query executed successfully (2.35 sec)
Ln:8 SELECT completed successfully
Ln:8 Standalone SELECT executed: 1 columns in the result set
Hello, fei!
Hello, fei!

tests come from http://www.hplsql.org/udf