Close json files after reading values

This prevents directory renames/deletes from hanging on Windows due to
the file handle still being open

download.py

@@ -133,6 +133,9 @@ def fix_plugin_directories(dest):
                 platform = data['platform']
                 guid = data['guid']
 
+                # Close json file
+                m.close()
+
                 expected_dir = platform + '_' + guid
                 expected_path = os.path.join(dest, expected_dir)
 
@@ -176,6 +179,9 @@ def download_plugins(data, dest):
                 data = json.load(m)
                 existing_version = data['version']
 
+                # Close json file
+                m.close()
+
                 # Version already matches
                 if version == existing_version:
                     print('NOTICE: Skipping "{}" download, "{}" already exists'