Fix managers to pass context necessary down the chain when purging. This should fix at least one quota calc error.

Fix another bug in hda manager regarding quota reduction -- quota usage must be calculated prior to actually purging, otherwise the disk usage is 0 and this does nothing.

Slight refactoring in manager purge -- we don't need to pass the user via context since we can just grab it where applicable from the history.

Fix purge when handling an anonymous user

lib/galaxy/managers/hdas.py

@@ -143,14 +143,18 @@ class HDAManager( datasets.DatasetAssociationManager,
         return ldda.to_history_dataset_association( history, add_to_history=True )
 
     # .... deletion and purging
-    def purge( self, hda, current_user=None, flush=True ):
+    def purge( self, hda, flush=True):
         """
         Purge this HDA and the dataset underlying it.
         """
+        user = hda.history.user or None
+        quota_amount_reduction = 0
+        if user:
+            quota_amount_reduction = hda.quota_amount( user )
         super( HDAManager, self ).purge( hda, flush=flush )
         # decrease the user's space used
-        if current_user:
-            current_user.total_disk_usage -= hda.quota_amount( current_user )
+        if quota_amount_reduction:
+            user.total_disk_usage -= quota_amount_reduction
         return hda
 
     # .... states

lib/galaxy/managers/histories.py

@@ -82,7 +82,6 @@ class HistoryManager( sharable.SharableModelManager, deletable.PurgableManagerMi
         Purge this history and all HDAs, Collections, and Datasets inside this history.
         """
         self.hda_manager.dataset_manager.error_unless_dataset_purge_allowed()
-
         # First purge all the datasets
         for hda in history.datasets:
             if not hda.purged: