ares: remove fd from multi fd set when ares is about to close the fd

ares: remove fd from multi fd set when ares is about to close the fd

When using c-ares for asyn dns, the dns socket fd was silently closed
by c-ares without curl being aware. curl would then 'realize' the fd
has been removed at next call of Curl_resolver_getsock, and only then
notify the CURLMOPT_SOCKETFUNCTION to remove fd from its poll set with
CURL_POLL_REMOVE. At this point the fd is already closed.

By using ares socket state callback (ARES_OPT_SOCK_STATE_CB), this
patch allows curl to be notified that the fd is not longer needed
for neither for write nor read. At this point by calling
Curl_multi_closed we are able to notify multi with CURL_POLL_REMOVE
before the fd is actually closed by ares.

In asyn-ares.c Curl_resolver_duphandle we can't use ares_dup anymore
since it does not allow passing a different sock_state_cb_data

Backported patch details:
https://github.com/curl/curl/commit/6765e6d9e6a32bb4fc666d744cb57e2d55d4e13b

Change-Id: I62b2d244cb0f38a4c4a76ad804c7fd69f9222484
Signed-off-by: Niraj Kumar Goit <niraj.g@samsung.com>