Wait for BackupPC_link to run before we take new sizes in our stat

So it won't send wrong comp_ratio of size values

zabbix_scripts/check_backuppc_sudo

@@ -64,7 +64,7 @@ if ( $host ) {
       # Push all the sizes in our data set to compute avg sizes
       # Exclude backup N°0 as it'll always have much more new data than normal backups
       # Also exclude if size is not defined. This can happen in BackupPC v3 when
-      # the link process is waiting for the nightly to finish
+      # the BackupPC_link process is waiting for the nightly to finish
       $sizes->add_data($backup->{sizeNew}) unless ( $backup->{num} == 0 || !$backup->{sizeNew} );
       $json->{bkp}++;
     }
@@ -73,13 +73,8 @@ if ( $host ) {
     my $i = ( $bpc_info[-1]->{type} =~ m/^full|incr$/ ) ? -1 : -2;
 
     $json->{errors}      = $bpc_info[$i]->{xferErrs};
-    $json->{new_size}    = $bpc_info[$i]->{sizeNew};
     $json->{duration}    = $bpc_info[$i]->{endTime} - $bpc_info[$i]->{startTime};
     $json->{type}        = $bpc_info[$i]->{type};
-    $json->{comp_ratio}  = ( $bpc_info[$i]->{sizeNew} > 0 ) ?
-        sprintf( "%.2f", 100 - ( $bpc_info[$i]->{sizeNewComp} * 100 / $bpc_info[$i]->{sizeNew} ) )
-          :
-        0;
 
     $json->{new_size_avg}    = int $sizes->mean;
     $json->{new_size_median} = int $sizes->median;
@@ -90,6 +85,15 @@ if ( $host ) {
     $json->{total_size}      = $sizes->sum + $json->{full_size} - 2 * $new_size_of_last_full;
     $json->{age}             = time - $bpc_info[$i]->{startTime};
 
+    # For newSize, we need to wait for BackupPC_link to run, which can be delayed
+    # if a nightly process is running. In this case, use the stats from the previous backup
+    $i = ( $backup->{sizeNew} ) ? -1 : -2;
+    $json->{new_size}    = $bpc_info[$i]->{sizeNew};
+    $json->{comp_ratio}  = ( $bpc_info[$i]->{sizeNew} > 0 ) ?
+        sprintf( "%.2f", 100 - ( $bpc_info[$i]->{sizeNewComp} * 100 / $bpc_info[$i]->{sizeNew} ) )
+          :
+        0;
+
     $json->{max_errors} = $conf->{MaxXferError} || 0;
   }
 } elsif ( $entity ) {