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/devmapper/mount.go

@@ -0,0 +1,89 @@
+// +build linux
+
+package devmapper
+
+import (
+	"bytes"
+	"fmt"
+	"os"
+	"path/filepath"
+	"syscall"
+)
+
+// FIXME: this is copy-pasted from the aufs driver.
+// It should be moved into the core.
+
+// Mounted returns true if a mount point exists.
+func Mounted(mountpoint string) (bool, error) {
+	mntpoint, err := os.Stat(mountpoint)
+	if err != nil {
+		if os.IsNotExist(err) {
+			return false, nil
+		}
+		return false, err
+	}
+	parent, err := os.Stat(filepath.Join(mountpoint, ".."))
+	if err != nil {
+		return false, err
+	}
+	mntpointSt := mntpoint.Sys().(*syscall.Stat_t)
+	parentSt := parent.Sys().(*syscall.Stat_t)
+	return mntpointSt.Dev != parentSt.Dev, nil
+}
+
+type probeData struct {
+	fsName string
+	magic  string
+	offset uint64
+}
+
+// ProbeFsType returns the filesystem name for the given device id.
+func ProbeFsType(device string) (string, error) {
+	probes := []probeData{
+		{"btrfs", "_BHRfS_M", 0x10040},
+		{"ext4", "\123\357", 0x438},
+		{"xfs", "XFSB", 0},
+	}
+
+	maxLen := uint64(0)
+	for _, p := range probes {
+		l := p.offset + uint64(len(p.magic))
+		if l > maxLen {
+			maxLen = l
+		}
+	}
+
+	file, err := os.Open(device)
+	if err != nil {
+		return "", err
+	}
+	defer file.Close()
+
+	buffer := make([]byte, maxLen)
+	l, err := file.Read(buffer)
+	if err != nil {
+		return "", err
+	}
+
+	if uint64(l) != maxLen {
+		return "", fmt.Errorf("devmapper: unable to detect filesystem type of %s, short read", device)
+	}
+
+	for _, p := range probes {
+		if bytes.Equal([]byte(p.magic), buffer[p.offset:p.offset+uint64(len(p.magic))]) {
+			return p.fsName, nil
+		}
+	}
+
+	return "", fmt.Errorf("devmapper: Unknown filesystem type on %s", device)
+}
+
+func joinMountOptions(a, b string) string {
+	if a == "" {
+		return b
+	}
+	if b == "" {
+		return a
+	}
+	return a + "," + b
+}