fs: dlm: create midcomms nodes when configure

This patch puts the life of a midcomms node the same as a lowcomms
connection. The lowcomms connection lifetime was changed by commit
6f0b0b5d ("fs: dlm: remove dlm_node_addrs lookup list"). In the
future the midcomms node instances can be merged with lowcomms
connection structure as the lifetime is the same and states can be
controlled over values or flags.

Before midcomms nodes were generated during version detection. This is
not necessary anymore when the nodes are created when the cluster
manager configures DLM via configfs. When a midcomms node is created over
configfs it well set DLM_VERSION_NOT_SET as version. This indicates that
the version of the midcomms node is still unknown and need to be probed
via certain rcom messages.

Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>