LU-14536 obi2lnd: don't try to reconnect if there's no listener

LU-14536 obi2lnd: don't try to reconnect if there's no listener

For each discovery we try to reconnect up to retry_count times,
default to 5. during MDT mount process conf log, there will be
multiple discovery made for each OST.
If the OSTs are not up, the mount will have a long time out.

Lustre-change: https://review.whamcloud.com/42111
Lustre-commit: 67ba3ce23d32266eabd5f8c56fa78d65920455e8

Test-Parameters: trivial
Signed-off-by: Li Dongyang <dongyangli@ddn.com>
Change-Id: If1d854216d2f26089c52d3fb501092b7f48a444d
Reviewed-by: Serguei Smirnov <ssmirnov@whamcloud.com>
Reviewed-by: Amir Shehata <ashehata@whamcloud.com>
Reviewed-on: https://review.whamcloud.com/45896
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>