Fix a typo in disco_block_device so that removable devices are excluded

zabbix_scripts/disco_block_devices

@@ -7,13 +7,13 @@ my @blocks = grep { $_ !~ m/^\./ } readdir($dh);
 closedir($dh);
 my $json;
 foreach my $block (@blocks){
-    my $remouvable = 0;
-    if ( -e "/sys/block/$block/remouvable"){
-        open REMOUVABLE, "/sys/block/$block/remouvable";
-        $remouvable = join "", <REMOUVABLE>;
-        close REMOUVABLE;
-        chomp($remouvable);
-        next if ($remouvable eq '1');
+    my $removable = 0;
+    if ( -e "/sys/block/$block/removable"){
+        open REMOVABLE, "/sys/block/$block/removable";
+        $removable = join "", <REMOVABLE>;
+        close REMOVABLE;
+        chomp($removable);
+        next if ($removable eq '1');
     }
     my $dev = '/dev/' . $block;
     push @{$json->{data}}, { "{#BLOCKDEVICE}" => $dev };