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/github.com/google/go-cmp/cmp/internal/diff/diff.go

@@ -12,6 +12,13 @@
 // is more important than obtaining a minimal Levenshtein distance.
 package diff
 
+import (
+	"math/rand"
+	"time"
+
+	"github.com/google/go-cmp/cmp/internal/flags"
+)
+
 // EditType represents a single operation within an edit-script.
 type EditType uint8
 
@@ -112,6 +119,8 @@ func (r Result) Similar() bool {
 	return r.NumSame+1 >= r.NumDiff
 }
 
+var randInt = rand.New(rand.NewSource(time.Now().Unix())).Intn(2)
+
 // Difference reports whether two lists of lengths nx and ny are equal
 // given the definition of equality provided as f.
 //
@@ -159,6 +168,17 @@ func Difference(nx, ny int, f EqualFunc) (es EditScript) {
 	// A vertical edge is equivalent to inserting a symbol from list Y.
 	// A diagonal edge is equivalent to a matching symbol between both X and Y.
 
+	// To ensure flexibility in changing the algorithm in the future,
+	// introduce some degree of deliberate instability.
+	// This is achieved by fiddling the zigzag iterator to start searching
+	// the graph starting from the bottom-right versus than the top-left.
+	// The result may differ depending on the starting search location,
+	// but still produces a valid edit script.
+	zigzagInit := randInt // either 0 or 1
+	if flags.Deterministic {
+		zigzagInit = 0
+	}
+
 	// Invariants:
 	//	• 0 ≤ fwdPath.X ≤ (fwdFrontier.X, revFrontier.X) ≤ revPath.X ≤ nx
 	//	• 0 ≤ fwdPath.Y ≤ (fwdFrontier.Y, revFrontier.Y) ≤ revPath.Y ≤ ny
@@ -209,7 +229,7 @@ func Difference(nx, ny int, f EqualFunc) (es EditScript) {
 		if fwdFrontier.X >= revFrontier.X || fwdFrontier.Y >= revFrontier.Y || searchBudget == 0 {
 			break
 		}
-		for stop1, stop2, i := false, false, 0; !(stop1 && stop2) && searchBudget > 0; i++ {
+		for stop1, stop2, i := false, false, zigzagInit; !(stop1 && stop2) && searchBudget > 0; i++ {
 			// Search in a diagonal pattern for a match.
 			z := zigzag(i)
 			p := point{fwdFrontier.X + z, fwdFrontier.Y - z}