Prepare v2015.10-rc4

Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/Makefile b/Makefile
index 86a917f..8c0ca1b 100644
--- a/Makefile
+++ b/Makefile
@@ -1,7 +1,7 @@
 VERSION = 2015
 PATCHLEVEL = 10
 SUBLEVEL =
-EXTRAVERSION = -rc3
+EXTRAVERSION = -rc4
 NAME =
 
 # *DOCUMENTATION*