Ignore scanfc Invalid argument for rotctld

https://github.com/Hamlib/Hamlib/issues/1391

tests/rotctl_parse.c

@@ -417,6 +417,10 @@ static int scanfc(FILE *fin, const char *format, void *p)
         }
 
         if (ferror(fin)) { rig_debug(RIG_DEBUG_ERR, "%s: errno=%d, %s\n", __func__, errno, strerror(errno)); clearerr(fin); }
+        if (errno == 22) // invalid arg we will continue
+        {
+            continue;
+        }
 
         return ret;
     }