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/drivers/aufs/mount.go

@@ -0,0 +1,21 @@
+// +build linux
+
+package aufs
+
+import (
+	"os/exec"
+	"syscall"
+
+	"github.com/Sirupsen/logrus"
+)
+
+// Unmount the target specified.
+func Unmount(target string) error {
+	if err := exec.Command("auplink", target, "flush").Run(); err != nil {
+		logrus.Warnf("Couldn't run auplink before unmount %s: %s", target, err)
+	}
+	if err := syscall.Unmount(target, 0); err != nil {
+		return err
+	}
+	return nil
+}