Bug 17666: Revert "Bug 16685 [QA Followup] - Use Path::Tiny::slurp instead of File...

Bug 17666: Revert "Bug 16685 [QA Followup] - Use Path::Tiny::slurp instead of File::Slurp"

This reverts commit 7ac1bc35372990520a7c67870b2c702c41bbebcc.

On a kohadevbox:
Error flock (1) on
'/home/vagrant/kohaclone/installer/data/mysql/atomicupdate/bug_xxxx.perl':
No locks available at installer/data/mysql/updatedatabase.pl line 13637.

This is because Path::Tiny->slurp[_utf8] uses flocks which does not work
with NFS

Test plan:
Execute a .perl atomic update file on a kohadevbox
=> Without this patch you should get the flock error
=> With this patch the update should work fine

Signed-off-by: Josef Moravec <josef.moravec@gmail.com>
Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>