amend: removing redundant if condition

amend: removing redundant if condition

There is needless checking for the new commit hash not being equal to
the old commit hash. This condition will always be true at this point in the
code path and thus, can be removed safely. This commit removes the redundant
condition.

Test Plan:
ran the test suite.

Differential Revision: https://phab.mercurial-scm.org/D594

--- a/mercurial/cmdutil.py	Fri Sep 01 20:28:26 2017 +0000
+++ b/mercurial/cmdutil.py	Fri Sep 01 15:08:54 2017 -0700
@@ -3173,13 +3173,14 @@
             newid = repo.commitctx(new)
         finally:
             repo.ui.setconfig('phases', 'new-commit', ph, 'amend')
-        if newid != old.node():
-            # Reroute the working copy parent to the new changeset
-            repo.setparents(newid, nullid)
-            mapping = {old.node(): (newid,)}
-            if node:
-                mapping[node] = ()
-            scmutil.cleanupnodes(repo, mapping, 'amend')
+
+        # Reroute the working copy parent to the new changeset
+        repo.setparents(newid, nullid)
+        mapping = {old.node(): (newid,)}
+        if node:
+            mapping[node] = ()
+        scmutil.cleanupnodes(repo, mapping, 'amend')
+
     return newid
 
 def commiteditor(repo, ctx, subs, editform=''):