bitbake: replace 3 spaces with 4

A part of fetch2/__init__.py uses 3 spaces as the indent, I
think that they should be typos.

Signed-off-by: Robert Yang <liezhi.yang@windriver.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
bitbake: fetcher2: git.py: clean(): remove the .tar.gz.done

There was a problem:

$ bitbake xf86-video-omapfb -cfetch && bitbake xf86-video-omapfb -ccleanall

The git2_git.pingu.fi.xf86-video-omapfb.tar.gz has been removed from the
DL_DIR, but the git2_git.pingu.fi.xf86-video-omapfb.tar.gz.done still exists,
this is because the "open(ud.donestamp, 'w').close()" in try_mirror_url() will
create the git2_git.xxx.tar.gz.done, but no one removes it (the clean() in
fetch2/__init__.py removes the DL_DIR/git2/pkg.done)

This only happens on the git fetcher AFAIK.

[YOCTO #5688]

Signed-off-by: Robert Yang <liezhi.yang@windriver.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
bitbake: fetcher2: clean(): remove the .patch.done

There was a problem:

$ bitbake xf86-video-omapfb -cfetch && bitbake xf86-video-omapfb -ccleanall

Everything should be removed, but the
0006-omapfb-port-to-new-xserver-video-API.patch.done still exists in the
DL_DIR, this is because the clean() in the fetch2/__init__.py skips
removing the local file, so that it will skip removing the .done.

The local file (file://) isn't needed to be removed since it is not
downloaded into DL_DIR, but the .done should be removed, this patch will
remove the .done, and it doesn't remove anything else since the clean()
in local.py does nothing.

[YOCTO #5687]

Signed-off-by: Robert Yang <liezhi.yang@windriver.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>