Bug 6679 - [SIGNED-OFF] fix 3 perlcritic violations in C4/Items.pm

Bug 6679 - [SIGNED-OFF] fix 3 perlcritic violations in C4/Items.pm

"return" statement with explicit "undef" at line 508, column 44.  See page 199 of PBP.  (Severity: 5)
"return" statement with explicit "undef" at line 2267, column 5.  See page 199 of PBP.  (Severity: 5)
Variable declared in conditional statement at line 2642, column 21.  Declare variables outside of the condition.  (Severity: 5)

Signed-off-by: Jonathan Druart <jonathan.druart@biblibre.com>
Signed-off-by: Paul Poulain <paul.poulain@biblibre.com>