Don't detect mdadm RAID in containers

zabbix_scripts/disco_raid_mdadm

@@ -6,11 +6,13 @@ use JSON;
 my $json;
 @{$json->{data}} = ();
 
-open FILE, "< /proc/mdstat" or die "Can't open /proc/mdadm : $!";
-foreach my $line (<FILE>) {
+if (-x '/bin/systemd-detect-virt' && system('/bin/systemd-detect-virt', '-qc') != 0){
+  open FILE, "< /proc/mdstat" or die "Can't open /proc/mdadm : $!";
+  foreach my $line (<FILE>) {
     next unless ($line =~ m/^(md\d+)+\s*:/);
     my ($md,undef,$status,$level) = split(/\ /, $line);
     push @{$json->{data}}, {"{#DEVICE}" => $md, "{#STATUS}" => $status, "{#LEVEL}" => $level};
+  }
 }
 print to_json($json);
 exit(0);