Warn if a new service asserts the same condition as an existing one

Signed-off-by: Joachim Wiberg <troglobit@gmail.com>

src/svc.h

@@ -148,6 +148,7 @@ typedef struct svc {
 
 svc_t      *svc_new                (char *cmd, char *id, int type);
 int	    svc_del	           (svc_t *svc);
+void	    svc_validate	   (svc_t *svc);
 
 svc_t	   *svc_find	           (char *cmd, char *id);
 svc_t	   *svc_find_by_pid        (pid_t pid);