revert: revert clean files when only a change of flags is needed

tests/test-revert-flags

@@ -0,0 +1,17
+#!/bin/sh
+
+"$TESTDIR/hghave" execbit || exit 80
+
+hg init repo
+cd repo
+echo foo > foo
+chmod 644 foo
+hg ci -qAm '644'
+
+chmod 755 foo
+hg ci -qAm '755'
+
+echo '% reverting to rev 0'
+hg revert -a -r 0
+hg st
+hg diff --git

tests/test-revert-flags.out

@@ -0,0 +1,6
+% reverting to rev 0
+reverting foo
+M foo
+diff --git a/foo b/foo
+old mode 100755
+new mode 100644

mercurial/commands.py

@@ -2429,7 +2429,8 def revert(ui, repo, *pats, **opts):
                     if mfentry:
                         # if version of file is same in parent and target
                         # manifests, do nothing
-                        if pmf[abs] != mfentry:
+                        if (pmf[abs] != mfentry or
+                            pmf.flags(abs) != mf.flags(abs)):
                             handle(revert, False)
                     else:
                         handle(remove, False)