Build and install from GOPATH

* Rename 'vendor/src' -> 'vendor'
  * Ignore vendor/ instead of vendor/src/ for lint
* Rename 'cmd/client' -> 'cmd/ocic' to make it 'go install'able
* Rename 'cmd/server' -> 'cmd/ocid' to make it 'go install'able
* Update Makefile to build and install from GOPATH
* Update tests to locate ocid/ocic in GOPATH/bin
* Search for binaries in GOPATH/bin instead of PATH
* Install tools using `go get -u`, so they are updated on each run

Signed-off-by: Jonathan Yu <jawnsy@redhat.com>

vendor/github.com/containers/storage/pkg/ioutils/fswriters.go

@@ -0,0 +1,82 @@
+package ioutils
+
+import (
+	"io"
+	"io/ioutil"
+	"os"
+	"path/filepath"
+)
+
+// NewAtomicFileWriter returns WriteCloser so that writing to it writes to a
+// temporary file and closing it atomically changes the temporary file to
+// destination path. Writing and closing concurrently is not allowed.
+func NewAtomicFileWriter(filename string, perm os.FileMode) (io.WriteCloser, error) {
+	f, err := ioutil.TempFile(filepath.Dir(filename), ".tmp-"+filepath.Base(filename))
+	if err != nil {
+		return nil, err
+	}
+
+	abspath, err := filepath.Abs(filename)
+	if err != nil {
+		return nil, err
+	}
+	return &atomicFileWriter{
+		f:    f,
+		fn:   abspath,
+		perm: perm,
+	}, nil
+}
+
+// AtomicWriteFile atomically writes data to a file named by filename.
+func AtomicWriteFile(filename string, data []byte, perm os.FileMode) error {
+	f, err := NewAtomicFileWriter(filename, perm)
+	if err != nil {
+		return err
+	}
+	n, err := f.Write(data)
+	if err == nil && n < len(data) {
+		err = io.ErrShortWrite
+		f.(*atomicFileWriter).writeErr = err
+	}
+	if err1 := f.Close(); err == nil {
+		err = err1
+	}
+	return err
+}
+
+type atomicFileWriter struct {
+	f        *os.File
+	fn       string
+	writeErr error
+	perm     os.FileMode
+}
+
+func (w *atomicFileWriter) Write(dt []byte) (int, error) {
+	n, err := w.f.Write(dt)
+	if err != nil {
+		w.writeErr = err
+	}
+	return n, err
+}
+
+func (w *atomicFileWriter) Close() (retErr error) {
+	defer func() {
+		if retErr != nil || w.writeErr != nil {
+			os.Remove(w.f.Name())
+		}
+	}()
+	if err := w.f.Sync(); err != nil {
+		w.f.Close()
+		return err
+	}
+	if err := w.f.Close(); err != nil {
+		return err
+	}
+	if err := os.Chmod(w.f.Name(), w.perm); err != nil {
+		return err
+	}
+	if w.writeErr == nil {
+		return os.Rename(w.f.Name(), w.fn)
+	}
+	return nil
+}