Don't crash if we were unable to preprocess _any_ DPFs of a given size

Just skip outputting that data point instead

Docker/parse_logs

@@ -401,10 +401,12 @@ sub sum_preproc_online {
                     $maxnum = $1 if $1 > $maxnum;
                 }
             }
-            $pkey = $key;
-            $pkey =~ s/\d+$/$maxnum/;
-            my $scale = int(($triednum+$maxnum-1)/$maxnum);
-            $tdict->{$key} = &statscalesum($odict->{$key}, $pdict->{$pkey}, $scale);
+            if ($maxnum > 0) {
+                $pkey = $key;
+                $pkey =~ s/\d+$/$maxnum/;
+                my $scale = int(($triednum+$maxnum-1)/$maxnum);
+                $tdict->{$key} = &statscalesum($odict->{$key}, $pdict->{$pkey}, $scale);
+            }
         }
     }
 }