knsupdate: update man.8 and improve cmd_ttl return

refs #2137

Change-Id: I743b5b8abe9239d412c08d2cdf72c6d620cf9893

man/knsupdate.8in

@@ -93,15 +93,15 @@ cannot be set.
 .TP
 [\fBupdate\fR] \fBadd\fR \fIname\fR \fIttl\fR [\fIclass\fR] \fItype\fR \fIdata\fR
 
-Adds a request to add a new resource record into the zone. Please note that the
-\fIname\fR must be fully qualified domain name (zone name is not appended to it).
+Adds a request to add a new resource record into the zone. Please note that if the
+\fIname\fR is not fully qualified domain name, current \fIorigin\fR name is appended to it.
 
 .TP
-[\fBupdate\fR] \fBdel\fR[\fBete\fR] \fIname\fR \fIttl\fR [\fIclass\fR] \fItype\fR \fIdata\fR
+[\fBupdate\fR] \fBdel\fR[\fBete\fR] \fIname\fR [\fIttl\fR] [\fIclass\fR] [\fItype\fR] [\fIdata\fR]
 
-Adds a request to remove an existing resource record from the zone. There is
-the same requirement for the \fIname\fR parameter as in the \fBupdate add\fR
-command.
+Adds a request to remove all (or matching \fIclass\fR, \fItype\fR, \fIdata\fR)
+resource records from the zone. There is the same requirement for the
+\fIname\fR parameter as in the \fBupdate add\fR command. The \fIttl\fR item is ignored.
 
 .TP
 \fBshow\fR

src/utils/nsupdate/nsupdate_exec.c

@@ -594,9 +594,7 @@ int cmd_ttl(const char* lp, nsupdate_params_t *params)
 		return KNOT_EPARSEFAIL;
 	}
 
-	nsupdate_set_ttl(params, ttl);
-
-	return KNOT_EOK;
+	return nsupdate_set_ttl(params, ttl);
 }
 
 int cmd_debug(const char* lp, nsupdate_params_t *params)