scripts/make-release: Don't distribute .git directories

[crobinso@localhost qemu-2.0.0-rc0]$ find . -name .git
./dtc/.git
./pixman/.git

This is already done for the rom submodules.

https://bugs.launchpad.net/qemu/+bug/1224414
Signed-off-by: Cole Robinson <crobinso@redhat.com>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>

scripts/make-release

@@ -18,7 +18,7 @@ git clone "${src}" ${destination}
 pushd ${destination}
 git checkout "v${version}"
 git submodule update --init
-rm -rf .git roms/*/.git
+rm -rf .git roms/*/.git dtc/.git pixman/.git
 popd
 tar cfj ${destination}.tar.bz2 ${destination}
 rm -rf ${destination}