revert: issue "no changes needed" message for files missing on both side

When a file was marked as removed in the working copy and did not existed in the
target of the revert, we did not issued any message pointing that no change was
needed to the file (implicitly saying that revert had changed the file).

We now properly issue a message in this situation. Tests change in and handful
of case where the message was documented as missing.

mercurial/cmdutil.py

@@ -2466,7 +2466,11 b' def revert(ui, repo, ctx, parents, *pats'
             for table, (action, backup) in disptable:
                 if abs not in table:
                     continue
-                if action is not None:
+                if action is None:
+                    if exact:
+                        ui.warn(_('no changes needed to %s\n') % rel)
+
+                else:
                     handle(action, backup)
                 break
             else:

tests/test-revert.t

@@ -143,9 +143,10 b' exact match are more silent'
   $ hg st d
   R d
 
-should silently keep d removed
+should keep d removed
 
   $ hg revert -r0 d
+  no changes needed to d
   $ hg st d
   R d
 
@@ -1104,14 +1105,9 b' Misbehavior:'
 - fails to report no change to revert for
 |
 | - clean_clean
-| - added_revert
 | - clean_revert
 | - modified_revert
 | - removed_revert
-| - added_removed
-| - added_untracked-clean
-| - added_untracked-revert
-| - added_untracked-wc
 
   $ for file in `python ../gen-revert-cases.py filelist`; do
   >   echo '### revert for:' $file;
@@ -1123,14 +1119,19 b' Misbehavior:'
   ### revert for: added_deleted
   
   ### revert for: added_removed
+  no changes needed to added_removed
   
   ### revert for: added_revert
+  no changes needed to added_revert
   
   ### revert for: added_untracked-clean
+  no changes needed to added_untracked-clean
   
   ### revert for: added_untracked-revert
+  no changes needed to added_untracked-revert
   
   ### revert for: added_untracked-wc
+  no changes needed to added_untracked-wc
   
   ### revert for: added_wc