Bug 16104: Remove warnings "used only once: possible typo"

Bug 16104: Remove warnings "used only once: possible typo"

Since bug 11998, the following warnings are raised:
Name "Tie::Hash::FIELDS" used only once: possible typo at /usr/share/perl/5.22/fields.pm line 135.
Name "Cache::RemovalStrategy::LRU::FIELDS" used only once: possible typo at /usr/share/perl/5.22/fields.pm line 135.
Name "Cache::RemovalStrategy::FIELDS" used only once: possible typo at /usr/share/perl/5.22/fields.pm line 135.

It comes from the Koha::Cache

103     if ( can_load( modules => { 'Cache::Memory' => undef } ) ) {

Test plan:
  perl -wc C4/AuthoritiesMarc.pm
should return green

QA note: this may have an impact on performance but I have not found any other workarounds.

NOTE: I applied 15870 to master, got the error (-v 2 -c 5), applied 16104,
rebased it in front, error disappeared (still only -c 5), rebased it at the end,
and signed off 16104.

Signed-off-by: Mark Tompsett <mtompset@hotmail.com>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Brendan Gallagher <bredan@bywatersolutions.com>