VOL-1497 : Add more control to kv/memory access

- Added kv locking mechanism (etcd only)
- (watch) control path access whenever possible
- (watch) use a transaction for updates and merge with memory
- cleaned up vendoring
- misc changes to fix exceptions found along the way

Amendments:

- Copyright header got removed in auto-generated file
- Changed default locking to false for KV list operation
- Updated backend api to allow the passing of locking parameter

Change-Id: Ie1a55d3ca8b9d92ae71a85ce42bb22fcf1419e2c
diff --git a/vendor/golang.org/x/sys/unix/zsyscall_dragonfly_amd64.go b/vendor/golang.org/x/sys/unix/zsyscall_dragonfly_amd64.go
index da9986d..ae9f1a2 100644
--- a/vendor/golang.org/x/sys/unix/zsyscall_dragonfly_amd64.go
+++ b/vendor/golang.org/x/sys/unix/zsyscall_dragonfly_amd64.go
@@ -1194,6 +1194,26 @@
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
+func Renameat(fromfd int, from string, tofd int, to string) (err error) {
+	var _p0 *byte
+	_p0, err = BytePtrFromString(from)
+	if err != nil {
+		return
+	}
+	var _p1 *byte
+	_p1, err = BytePtrFromString(to)
+	if err != nil {
+		return
+	}
+	_, _, e1 := Syscall6(SYS_RENAMEAT, uintptr(fromfd), uintptr(unsafe.Pointer(_p0)), uintptr(tofd), uintptr(unsafe.Pointer(_p1)), 0, 0)
+	if e1 != 0 {
+		err = errnoErr(e1)
+	}
+	return
+}
+
+// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
+
 func Revoke(path string) (err error) {
 	var _p0 *byte
 	_p0, err = BytePtrFromString(path)