netsock: Remove from Asterisk core.

This moves netsock.c / netsock.h to the chan_iax2 module.  netsock.h has
been marked deprecated since 13.0.0, chan_iax2 is the only remaining
user.

Change-Id: I28c6578043bac18de5ea608e136acec4f83d5dd3

channels/chan_iax2.c

@@ -99,7 +99,6 @@
 #include "asterisk/localtime.h"
 #include "asterisk/dnsmgr.h"
 #include "asterisk/devicestate.h"
-#include "asterisk/netsock.h"
 #include "asterisk/stringfields.h"
 #include "asterisk/linkedlists.h"
 #include "asterisk/astobj2.h"
@@ -122,6 +121,7 @@
 #include "iax2/include/provision.h"
 #include "iax2/include/codec_pref.h"
 #include "iax2/include/format_compatibility.h"
+#include "iax2/include/netsock.h"
 
 #include "jitterbuf.h"
 

channels/iax2/netsock.c

@@ -43,7 +43,7 @@
 #include <ifaddrs.h>
 #endif
 
-#include "asterisk/netsock.h"
+#include "include/netsock.h"
 #include "asterisk/netsock2.h"
 #include "asterisk/utils.h"
 #include "asterisk/astobj.h"