remote-bzr: fix prefix of tags

In the current transport-helper code, refs without namespaced refspecs
doesn't work correctly, so let's always used them.

Some people reported issues with 'git clone --mirror'

Signed-off-by: Felipe Contreras <felipe.contreras@gmail.com>
remote-hg: fix commit messages

git fast-import expects an extra newline after the commit message data,
but we are adding it only on hg-git compat mode, which is why the
bidirectionality tests pass.

We should add it unconditionally.

Signed-off-by: Felipe Contreras <felipe.contreras@gmail.com>
Merge branch 'fc/remote/bzr' into fc/master
Merge branch 'fc/remote/hg' into fc/master