Update kernel headers to v3.14.

Other changes:
- Modify update_all.py to skip ion header files when importing into aosp.
- Fix generate_uapi_headers.sh to handle imports from a linux-stable kernel.

Change-Id: I1ad81b9ccb063c21740f9875f2cc1238052cd4b3
diff --git a/libc/kernel/uapi/linux/keyctl.h b/libc/kernel/uapi/linux/keyctl.h
index 89854b5..941e0d5 100644
--- a/libc/kernel/uapi/linux/keyctl.h
+++ b/libc/kernel/uapi/linux/keyctl.h
@@ -67,4 +67,5 @@
 #define KEYCTL_INSTANTIATE_IOV 20
 /* WARNING: DO NOT EDIT, AUTO-GENERATED CODE - SEE TOP FOR INSTRUCTIONS */
 #define KEYCTL_INVALIDATE 21
+#define KEYCTL_GET_PERSISTENT 22
 #endif