Bug 10851: (follow-up) fix issues reported by QA script

Bug 10851: (follow-up) fix issues reported by QA script

This patch fixes following warnings:

 FAIL   C4/Serials.pm
   FAIL   valid
        Useless use of a constant (43) in void context
        Useless use of a constant (41) in void context
        Useless use of a constant (44) in void context
        Useless use of a constant (42) in void context
        Useless use of a constant (4) in void context

Signed-off-by: Katrin Fischer <Katrin.Fischer.83@web.de>
Signed-off-by: Galen Charlton <gmc@esilibrary.com>