correctly update dirstate after update+mode change (issue1456)

tests/test-up-issue1456

@@ -0,0 +1,17 b''
+#!/bin/sh
+
+rm -rf a
+hg init a
+cd a
+
+echo foo > foo
+hg ci -qAm0
+chmod +x foo
+hg ci -m1
+hg co -q 0
+echo dirty > foo
+sleep 1
+hg up -q
+cat foo
+hg st -A
+

tests/test-up-issue1456.out

@@ -0,0 +1,2 b''
+dirty
+M foo

mercurial/merge.py

@@ -369,7 +369,9 b' def recordupdates(repo, action, branchme'
                 repo.dirstate.forget(f)
         elif m == "f": # forget
             repo.dirstate.forget(f)
-        elif m in "ge": # get or exec change
+        elif m == "e": # exec change
+            repo.dirstate.normaldirty(f)
+        elif m == "g": # get
             if branchmerge:
                 repo.dirstate.normaldirty(f)
             else: