[WINESYNC] Elegantly handle empty 'files' and 'directories' lists.

Expand on Timo's commit 4b5a555.
We may encounter cases where either the 'directories' or 'files' lists
in the .cfg YAML files are empty, and we don't want the script to throw
an exception in that case.

Furthermore, explicitly check for such empty lists when calling PyGit2
index.add_all(...) function, because if it's called on a None or empty
list, _all_ untracked files in the selected git repository get added,
which is not what we want there.

sdk/tools/winesync/winesync.py

@@ -99,19 +99,16 @@ def create_or_checkout_wine_branch(self, wine_tag, wine_staging_tag):
     # Helper function for resolving wine tree path to reactos one
     # Note: it doesn't care about the fact that the file actually exists or not
     def wine_to_reactos_path(self, wine_path):
-        if wine_path in self.module_cfg['files']:
+        if self.module_cfg['files'] and (wine_path in self.module_cfg['files']):
             # we have a direct mapping
             return self.module_cfg['files'][wine_path]
 
         if not '/' in wine_path:
             # root files should have a direct mapping
             return None
 
-        if self.module_cfg['directories'] is None:
-            return None
-
         wine_dir, wine_file = os.path.split(wine_path)
-        if wine_dir in self.module_cfg['directories']:
+        if self.module_cfg['directories'] and (wine_dir in self.module_cfg['directories']):
             # we have a mapping for the directory
             return posixpath.join(self.module_cfg['directories'][wine_dir], wine_file)
 
@@ -295,8 +292,13 @@ def revert_staged_patchset(self):
         if not has_patches:
             return True
 
-        self.reactos_index.add_all([f for f in self.module_cfg['files'].values()])
-        self.reactos_index.add_all([f'{d}/*.*' for d in self.module_cfg['directories'].values()])
+        # Note: these path lists may be empty or None, in which case
+        # we should not call index.add_all(), otherwise we would add
+        # any untracked file present in the repository.
+        if self.module_cfg['files']:
+            self.reactos_index.add_all([f for f in self.module_cfg['files'].values()])
+        if self.module_cfg['directories']:
+            self.reactos_index.add_all([f'{d}/*.*' for d in self.module_cfg['directories'].values()])
         self.reactos_index.write()
 
         self.reactos_repo.create_commit(