Update redis with 2.8.13 and a much smaller image (~129MB instead of ~800MB)

library/redis

@@ -1,5 +1,5 @@
 # maintainer: InfoSiftr <[email protected]> (@infosiftr)
 
-latest: git://github.com/docker-library/redis@3e57fae5920dbcd28aee48b441ebe9e55dab17a4
-2.8: git://github.com/docker-library/redis@3e57fae5920dbcd28aee48b441ebe9e55dab17a4
-2.8.12: git://github.com/docker-library/redis@3e57fae5920dbcd28aee48b441ebe9e55dab17a4
+latest: git://github.com/docker-library/redis@9fcab2d41ba06d2a581e7ccfee856e86dbb91d3f
+2.8.13: git://github.com/docker-library/redis@9fcab2d41ba06d2a581e7ccfee856e86dbb91d3f
+2.8:    git://github.com/docker-library/redis@9fcab2d41ba06d2a581e7ccfee856e86dbb91d3f