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

The last correction to the tcp_connect_to_sock error exit path,
commit a89d63a159b1ba5833be2bef00adf8ad8caac8be, can free an already
freed socket, due to collision with a previous (incomplete) attempt
to fix the same issue, commit 311f6fc77c51926dbdfbeab0a5d88d70f01fa3f4.

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