MT#64527 ngcp-panel-create-keys: Add missing import

We need to import Fcntl for O_WRONLY.

Fixes: commit fb44ee879a
Change-Id: I3458e1ece61c230072d9f8e325cab5adc8cf07fb

tools_bin/ngcp-panel-create-keys

@@ -5,6 +5,7 @@ use warnings;
 
 use Getopt::Long qw(GetOptions);
 use Pod::Usage qw(pod2usage);
+use Fcntl;
 use File::Basename qw(fileparse);
 use File::Path qw(make_path);