dlm: fix double-release of socket in error exit path

The last correction to the tcp_connect_to_sock error exit path,
commit a89d63a1, can free an already
freed socket, due to collision with a previous (incomplete) attempt
to fix the same issue, commit 311f6fc7

.

Signed-off-by: Casey Dahlin <cdahlin@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>