tcp: bind tcp sockets after enabling the repair mode

Only sockets in the repair mode can be bound to the same
port a few time, what is required to restore tcp connects.

v2: move bind() into libsoccr
v3: fix an error message
Signed-off-by: Andrei Vagin <avagin@virtuozzo.com>
Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>