connmgr: Do not persist OpenFlow settings from one session to another.

connmgr: Do not persist OpenFlow settings from one session to another.

Each OpenFlow session should begin fresh, with settings that are the
default for OpenFlow, but the connection manager was mistakenly persisting
them from one session to the next for "primary" controllers.

This is a bug, but it is a long-standing one.  I found the problem by
inspection, not through a bug report, so I do not think that it causes much
harm in practice.

Signed-off-by: Ben Pfaff <blp@nicira.com>