app_rpt: Fix variable typing issue. (#440)

This function returns char*, but the variable is typed
const char* by mistake; this fixes that.

Resolves: #439

apps/app_rpt/rpt_manager.c

@@ -21,7 +21,7 @@ extern struct rpt rpt_vars[MAXRPTS];
 static char *ctime_no_newline(const time_t *clock)
 {
 	static char buf[32];
-	const char *cp;
+	char *cp;
 	size_t len;
 
 	cp = ctime_r(clock, buf);