REORG: connection: replace si_data_close() with conn_data_close()

This close function only applies to connection-specific parts and
the stream-interface entry may soon disappear. Move this to the
connection instead.
diff --git a/src/stream_interface.c b/src/stream_interface.c
index cf26b51..030c7c1 100644
--- a/src/stream_interface.c
+++ b/src/stream_interface.c
@@ -27,6 +27,7 @@
 #include <common/time.h>
 
 #include <proto/buffers.h>
+#include <proto/connection.h>
 #include <proto/fd.h>
 #include <proto/frontend.h>
 #include <proto/sock_raw.h>
@@ -230,7 +231,7 @@
 		si->state = SI_ST_DIS;
 		si->exp = TICK_ETERNITY;
 
-		si_data_close(si);
+		conn_data_close(&si->conn);
 		if (si->release)
 			si->release(si);
 	}
@@ -267,7 +268,7 @@
 		si->state = SI_ST_DIS;
 		/* fall through */
 
-		si_data_close(si);
+		conn_data_close(&si->conn);
 		if (si->release)
 			si->release(si);
 	default: