Revert "Use DiffFormatter for commit_delta fact to improve performance."

This reverts commit 7e0cfa9f72123fb091d98c28b59ede18d54044cd.

Reason for revert: Need to update existing usage first.

Change-Id: I18c0f9aa92cacb670e76bddea16708ed2963da22

Documentation/prolog-change-facts.txt

diff --git a/Documentation/prolog-change-facts.txt b/Documentation/prolog-change-facts.txt
index fbda0f9..e5b4140 100644
--- a/Documentation/prolog-change-facts.txt
+++ b/Documentation/prolog-change-facts.txt
@@ -90,21 +90,16 @@
     |True if any file name from the last patch set matches the given regex.
 
 |`commit_delta/3`           |`commit_delta('\\.java$', T, P)`
-    |Returns the change type (via `T`) and new path (via `P`).
+    |Returns the change type (via `T`) and path (via `P`), if the change type
+    is `rename`, it also returns the old path. If the change type is `rename`, it
+    returns a delete for old path and an add for new path. If the change type
+    is `copy`, an add is returned along with new path.
 
     Possible values for the change type are the following symbols: `add`,
     `modify`, `delete`, `rename`, `copy`
 
-    Depending on the change type, new path is set as follows:
-    For add, the file being created. For modify, the same as the old path.
-    For delete, nil. For copy/rename, the destination path.
-
 |`commit_delta/4`           |`commit_delta('\\.java$', T, P, O)`
-    |Like `commit_delta/3` plus the old path (via `O`).
-
-    Depending on the change type, old path is set as follows:
-    For add, nil. For modify, the same as new path.
-    For delete, the file being deleted. For copy/rename, the original path.
+    |Like `commit_delta/3` plus the old path (via `O`) if applicable.
 
 |`commit_edits/2`           |`commit_edits('/pom.xml$', 'dependency')`
     |True if any of the files matched by the file name regex (first parameter)