LU-11269 ptlrpc: do not expose transient IDLE state

LU-11269 ptlrpc: do not expose transient IDLE state

to avoid cases when anyone sending an RPC observes the connection
in this state while it's going to reconnect right away.

Signed-off-by: Alex Zhuravlev <bzzz@whamcloud.com>
Change-Id: I9ca89051c4176fe321262f8b2f52969c382e401e
Reviewed-on: https://review.whamcloud.com/37523
Reviewed-by: Mike Pershin <mpershin@whamcloud.com>
Reviewed-by: James Simmons <jsimmons@infradead.org>
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>