Revert "stat_tracking_info(): only count real commits"

This reverts commit 19de5d69.
It produces a misleading output to decide if a merge can fast-forward.

Documentation/RelNotes-1.6.3.txt

@@ -69,10 +69,6 @@ Updates since v1.6.2
   with the 'edit' action in git-add -i/-p, you can abort the editor to
   tell git not to apply it.
 
-* The number of commits shown in "you are ahead/behind your upstream"
-  messages given by "git checkout" and "git status" used to count merge
-  commits; now it doesn't.
-
 * @{-1} is a new way to refer to the last branch you were on introduced in
   1.6.2, but the initial implementation did not teach this to a few
   commands.  Now the syntax works with "branch -m @{-1} newname".

remote.c

@@ -1413,10 +1413,9 @@ int stat_tracking_info(struct branch *branch, int *num_ours, int *num_theirs)
 	if (theirs == ours)
 		return 0;
 
-	/* Run "rev-list --no-merges --left-right ours...theirs" internally... */
+	/* Run "rev-list --left-right ours...theirs" internally... */
 	rev_argc = 0;
 	rev_argv[rev_argc++] = NULL;
-	rev_argv[rev_argc++] = "--no-merges";
 	rev_argv[rev_argc++] = "--left-right";
 	rev_argv[rev_argc++] = symmetric;
 	rev_argv[rev_argc++] = "--";