Drop unused code
route: switched route reqeust to dnet_trans_alloc_send_state() instead of handmade transaction. Switched route reply processing to dnet_add_state()
server: fixed socket structure leak if socket was not successfully initialized
trans: added comments about dnet_trans_alloc_send_state()
net: only connect to addresses whose sockets are set to -ENOENT when parsing array of dnet_addr_socket structure. It is possible to have -EEXIST there if given address already exist in the route table
route: new batch request completion logic

Completion function stores array of remote addresses when they
are coming from remote node (route reply commands). When transaction
is completed, we add multiple addresses using batch dnet_add_state().

This new operation is a bit more costly - it runs over all addresses,
checks whether they exist in the route table or not, connects to those
addresses which are not yet present in the route table,
sends, receives and processes REVERSE LOOKUP command (bunch of log cleanups there).

Previously route reply parsed reply and used ids received in ROUTE reply command.
It sends REVERSE LOOKUP now. This allows to unify code, drop old functions
and (!) use batch new dnet_add_state() method to connect to multiple nodes in parallel.