remote-hg: always point HEAD to master

Mercurial always checks out the 'default' branch, so there's no point in
complicating our lives trying to do something fancier, which causes
different behavior depending on whether the repository is local or
remote.

So let's always use 'default' (which we translate to 'master'), unless
we are in hg-git mode, which expects us to use the 'master' bookmark
instead.

Also, update the tests that used to check for different checkout
behaviors to simply check that the refs are there, remove unnecessary
ones, and fix the ones that expect something different.

Signed-off-by: Felipe Contreras <felipe.contreras@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

test-hg-hg-git.sh

@@ -27,7 +27,8 @@ fi
 
 # clone to a git repo with git
 git_clone_git () {
-	git clone -q "hg::$1" $2
+	git clone -q "hg::$1" $2 &&
+	(cd $2 && git checkout master && git branch -D default)
 }
 
 # clone to an hg repo with git
@@ -63,6 +64,7 @@ hg_push_git () {
 	cd $2
 	git checkout -q -b tmp &&
 	git fetch -q "hg::../$1" 'refs/tags/*:refs/tags/*' 'refs/heads/*:refs/heads/*' &&
+	git branch -D default &&
 	git checkout -q @{-1} &&
 	git branch -q -D tmp 2> /dev/null || true
 	)