Get job history line from job summary file

Inputs:  Parm1 = Job Instance UJP pathname
         Parm3 = 0=last line, 1=penultimate line, ...

Output:  Parm2 = Retrieved History line
         Parm2 = (empty) (indicates no such history line)

Returns: bracketed value (or -1 if no value in square brackets)

This function retrieves the last line of the job history when Parm3 is passed as zero.  When Parm3 is 1, the penultimate line is returned, and so on.  The line is returned in Parm2 and includes the inserted timestamp and the numeric value in square brackets.

When the function returns with an empty value in Parm2 there is no corresponding line in the history.