Add xattr name index for xattrs with the 'security' prefix. These are defined
in the ext(2|3|4)/xattr.h in the kernel. We use the EXT2 prefix for consistency
with e2fslibs naming.

Signed-off-by: Philip Tricca <flihp@twobit.us>

Index: e2fsprogs-1.42.9/lib/ext2fs/ext2_ext_attr.h
===================================================================
--- e2fsprogs-1.42.9.orig/lib/ext2fs/ext2_ext_attr.h
+++ e2fsprogs-1.42.9/lib/ext2fs/ext2_ext_attr.h
@@ -15,6 +15,9 @@
 /* Maximum number of references to one attribute block */
 #define EXT2_EXT_ATTR_REFCOUNT_MAX	1024
 
+/* Name indexes */
+#define EXT2_XATTR_INDEX_SECURITY               6
+
 struct ext2_ext_attr_header {
 	__u32	h_magic;	/* magic number for identification */
 	__u32	h_refcount;	/* reference count */