[network] main config file interface setting overrides dyn-mode setting

When setting a network interface in the main config file this should
be an override for the one set in the dynamic modes. Found thanks to the
feedback of pigzz

Signed-off-by: Philippe De Swert <philippe.deswert@jollamobile.com>

docs/usb_moded-doc.txt

@@ -88,9 +88,10 @@ mode = ask
 The other settings and config dirs will be handled later in the appsync and dynamic modes part.
 (This is optional and can be compiled out)
 
-There is also an optional network configuration. The default ip set for usb networking is 192.168.2.15 
-(for Meego/Nemo). However this can be configured by hand in the ini file also (optionally in a separate
-ini file which is possible due to config file merging).
+There is also an optional network configuration. Certain parts of this config will override the settings
+set in the dynamic mode configuration, like for example interface. The default ip set for usb networking
+is 192.168.2.15 (for Meego/Nemo). However this can be configured by hand in the ini file also
+(optionally in a separate ini file which is possible due to config file merging).
 
 For example:
 

src/usb_moded-network.c

@@ -91,15 +91,18 @@ static char* get_interface(struct mode_list_elem *data)
   char *interface = NULL;
   int check = 0;
 
-  if(data)
+  /* check main configuration before using
+     the information from the specific mode */
+  interface = (char *)get_network_interface();
+  /* no interface override specified, let's use the one
+     from the mode config */
+  if(data && !interface)
   {
 	if(data->network_interface)
 	{	
 		interface = strdup(data->network_interface);
 	}
   }
-  else
-  	interface = (char *)get_network_interface();
 
   if(interface != NULL)
 	check = check_interface(interface);
@@ -108,6 +111,7 @@ static char* get_interface(struct mode_list_elem *data)
   {
 	if(interface != NULL)
 		free((char *)interface);
+	/* no known interface configured and existing, falling back to usb0 */
 	interface = malloc(sizeof(default_interface)*sizeof(char));
 	strncpy(interface, default_interface, sizeof(default_interface));
   }