filemerge: only print out "merging f" output at premerge step

We're soon going to call this function twice, once for premerge and once for
merge. This makes sure the "merging" output only gets printed during the
premerge step.

mercurial/filemerge.py

@@ -487,10 +487,11 b' def _filemerge(premerge, repo, mynode, o'
     if mergetype == nomerge:
         return True, func(repo, mynode, orig, fcd, fco, fca, toolconf)
 
-    if orig != fco.path():
-        ui.status(_("merging %s and %s to %s\n") % (orig, fco.path(), fd))
-    else:
-        ui.status(_("merging %s\n") % fd)
+    if premerge:
+        if orig != fco.path():
+            ui.status(_("merging %s and %s to %s\n") % (orig, fco.path(), fd))
+        else:
+            ui.status(_("merging %s\n") % fd)
 
     ui.debug("my %s other %s ancestor %s\n" % (fcd, fco, fca))