Apply suggestions from code review

Co-authored-by: dgtlmoon <leigh@morresi.net>

changedetectionio/model/Watch.py

@@ -208,7 +208,7 @@ class model(dict):
         if not os.path.isdir(output_path):
             os.mkdir(output_path)
 
-        snapshot_fname = os.path.join(output_path, "previous.txt")
+        snapshot_fname = os.path.join(self.watch_data_dir, "previous.txt")
         logging.debug("Saving previous text {}".format(snapshot_fname))
 
         with open(snapshot_fname, 'wb') as f:
@@ -220,7 +220,6 @@ class model(dict):
     def get_previous_text(self):
         from os import path
 
-        output_path = os.path.join(self.__datastore_path, self['uuid'])
 
         snapshot_fname = os.path.join(output_path, "previous.txt")
         if self.history_n < 1:

changedetectionio/store.py

@@ -598,9 +598,9 @@ class ChangeDetectionStore:
 
 
             # Check if the previous.txt exists
-            if not os.path.exists(os.path.join(self.datastore_path, uuid, "previous.txt")):
+            if not os.path.exists(os.path.join(watch.watch_data_dir, "previous.txt")):
                 # Generate a previous.txt
-                with open(os.path.join(self.datastore_path, uuid, "previous.txt"), "wb") as f:
+                with open(os.path.join(watch.watch_data_dir, "previous.txt"), "wb") as f:
                     # Fill it with the latest history
                     latest_file_name = watch.history[watch.newest_history_key]
                     with open(latest_file_name, "rb") as f2: