Osmocom_CTRL_Adapter: Let the OS decide over the local port number

At the moment the function f_ipa_ctrl_start() is starting the IPA
emulation client with parameter -1 for local port. This is internally
translated to port number 9999, which is a fixed number. This makes
it impossible to have two control interfaces at the same time.

Lets use 0 as local port, so that the OS is selecting a free port
number automatically.

Change-Id: Ie6648f8f4c1e065c174868c35eb64ee034ace3ce
Related: OS#3645
diff --git a/library/Osmocom_CTRL_Adapter.ttcn b/library/Osmocom_CTRL_Adapter.ttcn
index a98ac29..f1002bd 100644
--- a/library/Osmocom_CTRL_Adapter.ttcn
+++ b/library/Osmocom_CTRL_Adapter.ttcn
@@ -29,7 +29,7 @@
 	map(vc_CTRL_IPA:IPA_PORT, system:IPA_CODEC_PT);
 	connect(vc_CTRL_IPA:IPA_CTRL_PORT, self:IPA_CTRL);
 
-	vc_CTRL_IPA.start(IPA_Emulation.main_client(bsc_host, bsc_port, "", -1,
+	vc_CTRL_IPA.start(IPA_Emulation.main_client(bsc_host, bsc_port, "", 0,
 						    c_IPA_default_ccm_pars, false));
 
 	/* wait for IPA CTRL link to connect and send UP */