Removed a line which generated a report like "NSE: Script Scanning

completed." due to two issues.  One is that we already have a
different line printed in verbose mode which looks like "Completed NSE
at 14:31, 0.27s elapsed".  The other problem is that this was being
printed in non-verbose mode when you specified an argument like
"--script ssl-cert".  We intentionally bump the verbose mode of
scripts when they are specified individually like that so they can
report more script results, but I don't think we need the NSE
infrastructure itself to become more verbose.

nse_main.lua

@@ -820,5 +820,4 @@ return function (hosts)
   end
 
   collectgarbage "collect";
-  print_verbose(1, "Script Scanning completed.");
 end