userspace/snmpd/Makefile: don't fail a build if snmptranslate is not available

It is good to have this command being executed, but build shall not fail
if this command is missing.

Signed-off-by: Adam Wujek <dev_public@wujek.eu>

userspace/snmpd/Makefile

@@ -89,7 +89,7 @@ $(SHLIB): $(OBJECTS)
 	$(CC) $(LDFLAGS) $^ -o $@
 
 $(OID_FILE): $(MIBS)
-	snmptranslate -Pu -Tz -M +./ -m ./$(MIBS) >$(OID_FILE)
+	snmptranslate -Pu -Tz -M +./ -m ./$(MIBS) >$(OID_FILE) || true
 
 clean:
 	rm -f $(SHLIB) $(OBJECTS)