mobile: Switch from removed cli option to vty port

Bind the mobile's to a random (chosen by the kernel) VTY port. The
CLI option was removed and I added a new VTY command to be able to
specify the port in addition to the address.


Change-Id: Ie40a2ba156ba5674d37a15eb30e5b2527e75fbe7
diff --git a/src/osmo_gsm_tester/templates/osmo-mobile.cfg.tmpl b/src/osmo_gsm_tester/templates/osmo-mobile.cfg.tmpl
index 395d6f4..0a2cd6d 100644
--- a/src/osmo_gsm_tester/templates/osmo-mobile.cfg.tmpl
+++ b/src/osmo_gsm_tester/templates/osmo-mobile.cfg.tmpl
@@ -1,3 +1,5 @@
+line vty
+ bind 127.0.0.1 0
 no gps enable
 no hide-default
 ms ${test.ms_number}