Update debian (2015-04-28 debootstraps)

This is especially for `jessie` to become `latest`, and to add `stretch`.

library/debian

@@ -1,31 +1,33 @@
 # maintainer: Tianon Gravi <[email protected]> (@tianon)
 
 # commits: (master..dist)
-#  - 188b272 2015-04-21 debootstraps
+#  - b637abe 2015-04-28 debootstraps
 
-8.0: git://github.com/tianon/docker-brew-debian@188b27233cedf32048ee12378e8f8c6fc0fc0cb4 jessie
-8: git://github.com/tianon/docker-brew-debian@188b27233cedf32048ee12378e8f8c6fc0fc0cb4 jessie
-jessie: git://github.com/tianon/docker-brew-debian@188b27233cedf32048ee12378e8f8c6fc0fc0cb4 jessie
+8.0: git://github.com/tianon/docker-brew-debian@b637abe5e26f8b283a28d63cdc0413926ed54596 jessie
+8: git://github.com/tianon/docker-brew-debian@b637abe5e26f8b283a28d63cdc0413926ed54596 jessie
+jessie: git://github.com/tianon/docker-brew-debian@b637abe5e26f8b283a28d63cdc0413926ed54596 jessie
+latest: git://github.com/tianon/docker-brew-debian@b637abe5e26f8b283a28d63cdc0413926ed54596 jessie
 
-oldstable: git://github.com/tianon/docker-brew-debian@188b27233cedf32048ee12378e8f8c6fc0fc0cb4 oldstable
+oldstable: git://github.com/tianon/docker-brew-debian@b637abe5e26f8b283a28d63cdc0413926ed54596 oldstable
 
-sid: git://github.com/tianon/docker-brew-debian@188b27233cedf32048ee12378e8f8c6fc0fc0cb4 sid
+sid: git://github.com/tianon/docker-brew-debian@b637abe5e26f8b283a28d63cdc0413926ed54596 sid
 
-6.0.10: git://github.com/tianon/docker-brew-debian@188b27233cedf32048ee12378e8f8c6fc0fc0cb4 squeeze
-6.0: git://github.com/tianon/docker-brew-debian@188b27233cedf32048ee12378e8f8c6fc0fc0cb4 squeeze
-6: git://github.com/tianon/docker-brew-debian@188b27233cedf32048ee12378e8f8c6fc0fc0cb4 squeeze
-squeeze: git://github.com/tianon/docker-brew-debian@188b27233cedf32048ee12378e8f8c6fc0fc0cb4 squeeze
+6.0.10: git://github.com/tianon/docker-brew-debian@b637abe5e26f8b283a28d63cdc0413926ed54596 squeeze
+6.0: git://github.com/tianon/docker-brew-debian@b637abe5e26f8b283a28d63cdc0413926ed54596 squeeze
+6: git://github.com/tianon/docker-brew-debian@b637abe5e26f8b283a28d63cdc0413926ed54596 squeeze
+squeeze: git://github.com/tianon/docker-brew-debian@b637abe5e26f8b283a28d63cdc0413926ed54596 squeeze
 
-stable: git://github.com/tianon/docker-brew-debian@188b27233cedf32048ee12378e8f8c6fc0fc0cb4 stable
+stable: git://github.com/tianon/docker-brew-debian@b637abe5e26f8b283a28d63cdc0413926ed54596 stable
 
-testing: git://github.com/tianon/docker-brew-debian@188b27233cedf32048ee12378e8f8c6fc0fc0cb4 testing
+stretch: git://github.com/tianon/docker-brew-debian@b637abe5e26f8b283a28d63cdc0413926ed54596 stretch
 
-unstable: git://github.com/tianon/docker-brew-debian@188b27233cedf32048ee12378e8f8c6fc0fc0cb4 unstable
+testing: git://github.com/tianon/docker-brew-debian@b637abe5e26f8b283a28d63cdc0413926ed54596 testing
 
-7.8: git://github.com/tianon/docker-brew-debian@188b27233cedf32048ee12378e8f8c6fc0fc0cb4 wheezy
-7: git://github.com/tianon/docker-brew-debian@188b27233cedf32048ee12378e8f8c6fc0fc0cb4 wheezy
-wheezy: git://github.com/tianon/docker-brew-debian@188b27233cedf32048ee12378e8f8c6fc0fc0cb4 wheezy
-latest: git://github.com/tianon/docker-brew-debian@188b27233cedf32048ee12378e8f8c6fc0fc0cb4 wheezy
+unstable: git://github.com/tianon/docker-brew-debian@b637abe5e26f8b283a28d63cdc0413926ed54596 unstable
 
-rc-buggy: git://github.com/tianon/dockerfiles@cbaa8629f8619689ff4caae5b209d2928bcae8be debian/rc-buggy
-experimental: git://github.com/tianon/dockerfiles@cbaa8629f8619689ff4caae5b209d2928bcae8be debian/experimental
+7.8: git://github.com/tianon/docker-brew-debian@b637abe5e26f8b283a28d63cdc0413926ed54596 wheezy
+7: git://github.com/tianon/docker-brew-debian@b637abe5e26f8b283a28d63cdc0413926ed54596 wheezy
+wheezy: git://github.com/tianon/docker-brew-debian@b637abe5e26f8b283a28d63cdc0413926ed54596 wheezy
+
+rc-buggy: git://github.com/tianon/dockerfiles@0b288b65558ebc0fb0d7b457294a8ae52d9b0609 debian/rc-buggy
+experimental: git://github.com/tianon/dockerfiles@0b288b65558ebc0fb0d7b457294a8ae52d9b0609 debian/experimental