LU-17687 utils: Netlink doesn't return for missing MGS device

LU-17687 utils: Netlink doesn't return for missing MGS device

If the MGS is down then yaml_get_device_index() will fail to
contact the Netlink layer on the MGS server. When it fails
the bool done is still set to true which causes it to go into
a loop. The proper solution is to break on emitter failure of
any kind to the end of the function to cleanup the parser
and netlink socket.

Change-Id: Ia25000dd86fd2c5f46f5de24f9a5f391c373fea4
Signed-off-by: James Simmons <jsimmons@infradead.org>
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/55881
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Arshad Hussain <arshad.hussain@aeoncomputing.com>
Reviewed-by: Jian Yu <yujian@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>