Bug 11058: fix compilation warning in C4::Record

Bug 11058: fix compilation warning in C4::Record

A routine declares two lexical variables named $stylesheet.
This patch renames the second to keep code clearer and
avoid propagating compile time warnings

Signed-off-by: Mark Tompsett <mtompset@hotmail.com>
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>
Passes koha-qa.pl, works as advertised!

Signed-off-by: Galen Charlton <gmc@esilibrary.com>
(cherry picked from commit 6bad4db6a76d719ad6ac7fec2d4c7ec87ec8aa95)
Signed-off-by: Tomas Cohen Arazi <tomascohen@gmail.com>