Update storageos api dependency to 0.3.4

vendor/github.com/storageos/go-api/login.go

@@ -0,0 +1,46 @@
+package storageos
+
+import (
+	"encoding/json"
+	"errors"
+)
+
+var (
+	// LoginAPIPrefix is a partial path to the HTTP endpoint.
+	LoginAPIPrefix = "auth/login"
+	ErrLoginFailed = errors.New("Failed to get token from API endpoint")
+)
+
+// Login attemps to get a token from the API
+func (c *Client) Login() (token string, err error) {
+	resp, err := c.do("POST", LoginAPIPrefix, doOptions{data: struct {
+		User string `json:"username"`
+		Pass string `json:"password"`
+	}{c.username, c.secret}})
+
+	if err != nil {
+		if _, ok := err.(*Error); ok {
+			return "", ErrLoginFailed
+		}
+
+		return "", err
+	}
+
+	if resp.StatusCode != 200 {
+		return "", ErrLoginFailed
+	}
+
+	unmarsh := struct {
+		Token string `json:"token"`
+	}{}
+
+	if err := json.NewDecoder(resp.Body).Decode(&unmarsh); err != nil {
+		return "", err
+	}
+
+	if unmarsh.Token == "" {
+		return "", ErrLoginFailed
+	}
+
+	return unmarsh.Token, nil
+}