Upgrade versions of vendored libs

vendor/github.com/cockroachdb/errors/errbase/unwrap.go

@@ -27,6 +27,16 @@ package errbase
 // It supports both errors implementing causer (`Cause()` method, from
 // github.com/pkg/errors) and `Wrapper` (`Unwrap()` method, from the
 // Go 2 error proposal).
+//
+// UnwrapOnce treats multi-errors (those implementing the
+// `Unwrap() []error` interface as leaf-nodes since they cannot
+// reasonably be iterated through to a single cause. These errors
+// are typically constructed as a result of `fmt.Errorf` which results
+// in a `wrapErrors` instance that contains an interpolated error
+// string along with a list of causes.
+//
+// The go stdlib does not define output on `Unwrap()` for a multi-cause
+// error, so we default to nil here.
 func UnwrapOnce(err error) (cause error) {
 	switch e := err.(type) {
 	case interface{ Cause() error }:
@@ -39,6 +49,7 @@ func UnwrapOnce(err error) (cause error) {
 
 // UnwrapAll accesses the root cause object of the error.
 // If the error has no cause (leaf error), it is returned directly.
+// UnwrapAll treats multi-errors as leaf nodes.
 func UnwrapAll(err error) error {
 	for {
 		if cause := UnwrapOnce(err); cause != nil {
@@ -49,3 +60,12 @@ func UnwrapAll(err error) error {
 	}
 	return err
 }
+
+// UnwrapMulti access the slice of causes that an error contains, if it is a
+// multi-error.
+func UnwrapMulti(err error) []error {
+	if me, ok := err.(interface{ Unwrap() []error }); ok {
+		return me.Unwrap()
+	}
+	return nil
+}