ecore_con: Fix connect() handling

If connect() returns 0, we must send the ECORE_CON_EVENT_SERVER_ADD event
because it wont be given by select(). select() will ONLY notice it if connect
returns -1 with errno set to EINPROGRESS.

This bug is reproductible with 100% chance using ecore_con_telnet_client example
from https://github.com/gfriloux/examples if you connect to 127.0.0.1 instead of
of an external network ip, under FreeBSD (and likely any BSD).

Seems very rare to trigger it under GNU/Linux as it seems that connect()
doesnt want to return 0 when having non blocking sockets (or is too slow),
but it seems i was having this bug too on production servers, without being
ever able to reproduce it.