namespace: perlcritic warnings

Use local file handle not global.
Make loop and other variables local in scope.

Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Cc: Hui Zhu <teawater@gmail.com>
Cc: Cong Wang <amwang@redhat.com>
Cc: Michal Marek <mmarek@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Michal Marek <mmarek@suse.cz>