If error happens while connecting, nexus state is changed to error.
if nexus is closed, it removed from the cache without waiting for timeout.
nexus is kept in the cache until removed. new nexus will not refer the old
one.

Change-Id: I5042b2ecfa3744ce9b593f8d77f0fcae74737363
Signed-off-by: Eyal Salomon <esalomon@mellanox.com>