changeset_printer: hide manifest node for workingctx

Because workingctx has no manifest, it makes sense to hide "manifest:" row
completely.

mercurial/cmdutil.py

@@ -1151,7 +1151,7 @@ class changeset_printer(object):
                           % (pctx.rev(), hexfunc(pctx.node())),
                           label=label)
 
-        if self.ui.debugflag:
+        if self.ui.debugflag and rev is not None:
             mnode = ctx.manifestnode()
             # i18n: column positioning for "hg log"
             self.ui.write(_("manifest:    %d:%s\n") %

tests/test-log.t

@@ -1633,6 +1633,15 @@ working-directory revision requires special treatment
   $ hg log -r 'wdir()' -q
   0:65624cd9070a+
 
+  $ hg log -r 'wdir()' --debug
+  changeset:   0:65624cd9070a035fa7191a54f2b8af39f16b0c08+
+  phase:       draft
+  parent:      0:65624cd9070a035fa7191a54f2b8af39f16b0c08
+  parent:      -1:0000000000000000000000000000000000000000
+  user:        test
+  date:        [A-Za-z0-9:+ ]+ (re)
+  extra:       branch=default
+  
 Check that adding an arbitrary name shows up in log automatically
 
   $ cat > ../names.py <<EOF