Network: let add-ons replace themselves by name.

* Ie. an add-on "Super duper service" in ~/config will override
  one with the same name in /system (and non-packaged in packaged,
  etc.).
* Fixed size of the scroller to ignore the content size vertically.

src/preferences/network/NetworkWindow.cpp

@@ -126,6 +126,7 @@ NetworkWindow::NetworkWindow()
 
 	BScrollView* scrollView = new BScrollView("ScrollView", fListView,
 		0, false, true);
+	scrollView->SetExplicitMinSize(BSize(B_SIZE_UNSET, 42));
 
 	fAddOnShellView = new BView("add-on shell", 0,
 		new BGroupLayout(B_VERTICAL));
@@ -349,6 +350,11 @@ NetworkWindow::_ScanAddOns()
 	BPathFinder::FindPaths(B_FIND_PATH_ADD_ONS_DIRECTORY, "Network Settings",
 		paths);
 
+	// Collect add-on paths by name, so that each name will only be
+	// loaded once.
+	typedef std::map<BString, BPath> PathMap;
+	PathMap addOnMap;
+
 	for (int32 i = 0; i < paths.CountStrings(); i++) {
 		BDirectory directory(paths.StringAt(i));
 		BEntry entry;
@@ -357,6 +363,15 @@ NetworkWindow::_ScanAddOns()
 			if (entry.GetPath(&path) != B_OK)
 				continue;
 
+			if (addOnMap.find(path.Leaf()) == addOnMap.end())
+				addOnMap.insert(std::pair<BString, BPath>(path.Leaf(), path));
+		}
+	}
+
+	for (PathMap::const_iterator iterator = addOnMap.begin();
+			iterator != addOnMap.end(); iterator++) {
+		const BPath& path = iterator->second;
+
 		image_id image = load_add_on(path.Path());
 		if (image < 0) {
 			printf("Failed to load %s addon: %s.\n", path.Path(),
@@ -372,9 +387,8 @@ NetworkWindow::_ScanAddOns()
 			B_SYMBOL_TYPE_TEXT, (void**)&instantiateAddOn);
 		if (status != B_OK) {
 			// No "addon instantiate function" symbol found in this addon
-				printf("No symbol \"instantiate_network_settings_add_on\" "
+			printf("No symbol \"instantiate_network_settings_add_on\" found "
-					"found in %s addon: not a network setup addon!\n",
+				"in %s addon: not a network setup addon!\n", path.Path());
-					path.Path());
 			unload_add_on(image);
 			continue;
 		}
@@ -423,7 +437,6 @@ NetworkWindow::_ScanAddOns()
 		_SortItemsUnder(fDialUpItem);
 		_SortItemsUnder(fOtherItem);
 	}
-	}
 
 	fListView->SortItemsUnder(NULL, true,
 		NetworkWindow::_CompareTopLevelListItems);