ipmonitor: match user option 'all' before 'all-nsid'

ipmonitor: match user option 'all' before 'all-nsid'

'ip monitor all' is broken on older kernels.
This patch fixes 'ip monitor all' to match
'all' and not 'all-nsid'.

It moves parsing arg 'all-nsid' to after parsing
'all'.

Before:
$ip monitor all
NETLINK_LISTEN_ALL_NSID: Protocol not available

After:
$ip monitor all
[NEIGH]Deleted 10.0.0.1 dev eth1 lladdr c4:54:44:4f:b2:dd STALE

Fixes: 449b824ad196 ("ipmonitor: allows to monitor in several netns")
Signed-off-by: Roopa Prabhu <roopa@cumulusnetworks.com>
Acked-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>