say.c: correct time for polish

In ast_say_date_with_format_pl(), change ast_say_number() to
use tm_sec instead of tm_mn.

(closes issue ASTERISK-22856)
Reported by: Robert Mordec
Review: https://reviewboard.asterisk.org/r/3082/
Patches:
     say.c.patch uploaded by veilen (license 6555)


git-svn-id: http://svn.asterisk.org/svn/asterisk/branches/1.8@404456 f38db490-d61c-443f-a65b-d21fe96a405b