Bug 7567: (code cleanup) remove finish calls

Bug 7567: (code cleanup) remove finish calls

"When all the data has been fetched from a SELECT statement,
the driver will automatically call finish for you. So you should
not call it explicitly except when you know that you've not
fetched all the data from a statement handle and the handle
won't be destroyed soon."
(http://search.cpan.org/~timb/DBI-1.627/DBI.pm#finish)

All the $sth variables were scoped within the functions,
and would be destroyed immediately. Additionally, there was
one after a SELECT, for only a single idnew, and so it was
not necessary.

TEST PLAN
---------
1) prove -v t/db_dependent/NewsChannels.t
2) apply patch
3) prove -v t/db_dependent/NewsChannels.t

Signed-off-by: Chris Cormack <chris@bigballofwax.co.nz>
ok 1 - use C4::NewsChannels;
ok 2 - Successfully added the first dummy news item!
ok 3 - Successfully added the second dummy news item!
ok 4 - Successfully updated second dummy news item!
ok 5 - Successfully tested get_opac_new id1!
ok 6 - Successfully tested get_opac_new id2!
ok 7 - Successfully tested get_opac_news!
ok 8 - Successfully tested GetNewsToDisplay!

Signed-off-by: Jonathan Druart <jonathan.druart@biblibre.com>
Signed-off-by: Galen Charlton <gmc@esilibrary.com>