Do not fail the takeip event if the "ip addr add ..." command failed.
Let the event complete successfully. the local recovery daemon will check that we have the address and reissue takip othervise.
There are several reasons why "ip addr add " can fail, one is a misconfiguration
anothe ris that for ipv6 the stack is a lot more picky than for ipv4. for examplke this WILL fail in ipv6 if there is a duplicate ip address on the network.
thus this check could cause rolling-recoveries which is why it has to go