More conversions to rig_flush

https://github.com/Hamlib/Hamlib/issues/307

tests/ampctl_parse.c

@@ -1937,7 +1937,7 @@ declare_proto_amp(send_cmd)
 
     rs = &amp->state;
 
-    serial_flush(&rs->ampport);
+    rig_flush(&rs->ampport);
 
     retval = write_block(&rs->ampport, bufcmd, cmd_len);
 

tests/rigctl_parse.c

@@ -4394,7 +4394,7 @@ declare_proto_rig(send_cmd)
 
     rs = &rig->state;
 
-    serial_flush(&rs->rigport);
+    rig_flush(&rs->rigport);
 
     rig_debug(RIG_DEBUG_TRACE, "%s: rigport=%d, bufcmd=%s, cmd_len=%d\n", __func__,
               rs->rigport.fd, hasbinary(bufcmd) ? "BINARY" : bufcmd, cmd_len);

tests/rigctlcom.c

@@ -614,7 +614,7 @@ int main(int argc, char *argv[])
         char *stop_set = ";\n\r";
 
         memset(ts2000, 0, sizeof(ts2000));
-        serial_flush(&my_com);  // get rid of anything in the queue
+        rig_flush(&my_com);  // get rid of anything in the queue
 
         status = read_string(&my_com,
                              ts2000,

tests/rotctl_parse.c

@@ -1959,7 +1959,7 @@ declare_proto_rot(send_cmd)
 
     rs = &rot->state;
 
-    serial_flush(&rs->rotport);
+    rig_flush(&rs->rotport);
 
     retval = write_block(&rs->rotport, bufcmd, cmd_len);