Initial checkin from CRI-O repo

Signed-off-by: Matthew Heon <matthew.heon@gmail.com>

vendor/github.com/containers/storage/pkg/promise/promise.go

@@ -0,0 +1,11 @@
+package promise
+
+// Go is a basic promise implementation: it wraps calls a function in a goroutine,
+// and returns a channel which will later return the function's return value.
+func Go(f func() error) chan error {
+	ch := make(chan error, 1)
+	go func() {
+		ch <- f()
+	}()
+	return ch
+}