Fixed jrc_set_chan

set_chan() was correctly creating and sending the command, and returning RIG_OK. However, radio was actually ignoring it because command wasn't terminated with a CR. This is now corrected.

(cherry picked from commit aa39d6a618)

rigs/jrc/jrc.c

@@ -1459,6 +1459,8 @@ int jrc_set_chan(RIG *rig, vfo_t vfo, const channel_t *chan)
                  chan->levels[rig_setting2idx(RIG_LEVEL_AGC)].i);
     }
 
+    cmdbuf[priv->mem_len - 1] = 0x0d;
+ 
     return jrc_transaction(rig, cmdbuf, strlen(cmdbuf), NULL, NULL);
 }