ctrl: Don't expose write_queue in ctrl_cmd_send() api

ctrl_cmd_send() should always have taken a 'struct ctrl_connection'
as argument, not directly its write_queue member.

Let's offer a ctrl_cmd_send2() which fixes the problem, and deprecate
the old ctrl_cmd_send().

Related: OS#5751
Change-Id: Ic81af56e7ea6921ba39168727ef64c308e9c6754
diff --git a/include/osmocom/ctrl/control_if.h b/include/osmocom/ctrl/control_if.h
index 98cd100..e262d9e 100644
--- a/include/osmocom/ctrl/control_if.h
+++ b/include/osmocom/ctrl/control_if.h
@@ -28,7 +28,8 @@
 };
 
 
-int ctrl_cmd_send(struct osmo_wqueue *queue, struct ctrl_cmd *cmd);
+int ctrl_cmd_send(struct osmo_wqueue *queue, struct ctrl_cmd *cmd) OSMO_DEPRECATED("Use ctrl_cmd_send2() instead.");
+int ctrl_cmd_send2(struct ctrl_connection *ccon, struct ctrl_cmd *cmd);
 int ctrl_cmd_send_trap(struct ctrl_handle *ctrl, const char *name, char *value);
 struct ctrl_handle *ctrl_handle_alloc(void *ctx, void *data, ctrl_cmd_lookup lookup);
 struct ctrl_handle *ctrl_handle_alloc2(void *ctx, void *data,