Resolves: bug 245248
    Description: dsgw doesn't escape filename in error message
    Reviewed by: nhosoi (Thanks!)
    Fix Description: Do 2 passes on the input form data.  In the first pass,
    convert hex escapes (%xx) to the actual char.  In the second pass, if the
    char is one of the characters we must escape, convert to the html escape
    form (e.g. '&' to "&") then write to output string.  This way we can
    catch cases where "%xx" evaluates to '&' for example.
    Platforms tested: RHEL5 x86_64
    Flag day: no
    Doc: no