rebase: vendor dependencies for Vault API

Uses github.com/libopenstorage/secrets to communicate with Vault. This
removes the need for maintaining our own limited Vault APIs.

By adding the new dependency, several other packages got updated in the
process. Unused indirect dependencies have been removed from go.mod.

Signed-off-by: Niels de Vos <ndevos@redhat.com>

vendor/google.golang.org/protobuf/internal/descopts/options.go

@@ -0,0 +1,29 @@
+// Copyright 2019 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package descopts contains the nil pointers to concrete descriptor options.
+//
+// This package exists as a form of reverse dependency injection so that certain
+// packages (e.g., internal/filedesc and internal/filetype can avoid a direct
+// dependency on the descriptor proto package).
+package descopts
+
+import pref "google.golang.org/protobuf/reflect/protoreflect"
+
+// These variables are set by the init function in descriptor.pb.go via logic
+// in internal/filetype. In other words, so long as the descriptor proto package
+// is linked in, these variables will be populated.
+//
+// Each variable is populated with a nil pointer to the options struct.
+var (
+	File           pref.ProtoMessage
+	Enum           pref.ProtoMessage
+	EnumValue      pref.ProtoMessage
+	Message        pref.ProtoMessage
+	Field          pref.ProtoMessage
+	Oneof          pref.ProtoMessage
+	ExtensionRange pref.ProtoMessage
+	Service        pref.ProtoMessage
+	Method         pref.ProtoMessage
+)