chroot support in package kit: style fixes

- Catching an exception in the normal flow is not a good thing, instead,
  test before calling the function (I've been doing too much python
  lately)
- Avoid using uninitialized nodeRef if there is no system root and also
  no specified root in the message.

Thanks to Ingo or the code review.

src/kits/package/manager/PackageManager.cpp

@@ -110,11 +110,13 @@ BPackageManager::Init(uint32 flags)
 		// well. But we can easily filter those out.
 		_AddInstalledRepository(fSystemRepository);
 
-		try {
-			if (!fSystemRepository->IsInstalled())
+		if (!fSystemRepository->IsInstalled())
+		{
+			// Only add the home repository if the directory exists
+			BPath path;
+			status_t error = find_directory(B_USER_PACKAGES_DIRECTORY, &path);
+			if (error == B_OK && BEntry(path.Path()).Exists())
 				_AddInstalledRepository(fHomeRepository);
-		} catch(BFatalErrorException& exception) {
-			// No home repository found. This is ok for haikuporter chroots.
 		}
 	}
 

src/servers/package/PackageDaemon.cpp

@@ -93,8 +93,9 @@ PackageDaemon::MessageReceived(BMessage* message)
 
 			if (fSystemRoot != NULL && (error != B_OK
 					|| fSystemRoot->NodeRef() == nodeRef))
+			{
 				fSystemRoot->HandleRequest(DetachCurrentMessage());
-			else {
+			} else if (error == B_OK) {
 				Root* root = _FindRoot(nodeRef);
 				if (root != NULL) {
 					root->HandleRequest(DetachCurrentMessage());