Catch exceptions when matching configured clusters hosts
Catch exceptions when matching configured clusters hosts

During cluster linking, the host to be linked gets its IP address
resolved in order to get matched against the currently configured ones.

Resolving configured clusters IP address might throw an exception (when
they are not reachable anymore), this continues silently in such cases.

kensipe/dcos-cli,dcos/dcos-cli,kensipe/dcos-cli,dcos/dcos-cli,dcos/dcos-cli,dcos/dcos-cli,kensipe/dcos-cli,kensipe/dcos-cli,kensipe/dcos-cli,dcos/dcos-cli