Display Correct Error For Addrlabel Info

Display Correct Error For Addrlabel Info

The command "ip addrlabel add/del" displays incorrect error message when provided with insufficient inputs. This patch fixes it in par with "ip addr add/del".

Currently:
# ./ip addrlabel add
RTNETLINK answers: Numerical result out of range

# ./ip addr add
Not enough information: "dev" argument is required.

After patch:
# ./ip addrlabel add
Not enough information: "prefix" argument is required.

Signed-off-by: Varun Chandramohan <varunc@linux.vnet.ibm.com>
Signed-off-by: Stephen Hemminger <stephen.hemminger@vyatta.com>