fix: warnings on crystal 0.34

Author: stakach

shard.yml

@@ -1,5 +1,5 @@
 name: snmp
-version: 0.9.2
+version: 0.9.3
 
 dependencies:
   bindata:

src/snmp/helpers/if_entry.cr

@@ -47,6 +47,9 @@ class SNMP
           @out_errors = varbind.get_unsigned32
         when "1.3.6.1.2.1.2.2.1.21"
           @out_qlen = varbind.get_unsigned32
+        else
+          # We are not sure what this entry is
+          # safe to ignore
         end
       end
     end