Longhorn v0.4.0 release

Sync with Longhorn Manager

commit 9cde3deb1d449733e525aeb2d710ce4789d73abf
Author: Sheng Yang <sheng@yasker.org>
Date:   Thu Feb 21 14:52:59 2019 -0800

    Longhorn v0.4.0-rc2 release

Sync with Longhorn Manager

commit ccdccee7b3ac8d254fc36fefa9acd6a091df624e
Author: Sheng Yang <sheng@yasker.org>
Date:   Wed Feb 20 13:59:32 2019 -0800

    Longhorn v0.4.0-rc1 release

Merge pull request longhorn#373 from rancher/v0.3.3

Longhorn v0.3.3 release

Longhorn v0.3.3-rc1 release

Longhorn v0.3.2 release

Engine image: rancher/longhorn-engine:v0.3.0
Manager image: rancher/longhorn-manager:v0.3.2
UI Image: rancher/longhorn-ui:v0.3.2

Changelog:
1. Fix CSI support for Kubernetes v1.12
2. Fix unable to delete nodes which already have been removed from Kubernetes
3. Add the Upgrade Checker to allow automatically checking for the new version of Longhorn.

Rancher Longhorn App Chart:
1. Longhorn App has been updated to use Rancher proxy. It means Longhorn UI now behind the Rancher server authentication.
2. Rancher v2.1.x users can now uninstall Longhorn directly from the Rancher UI. Rancher v2.0.x users still need to follow the instruction to uninstall using the cleanup script.

Sync with Longhorn Manager

commit f8e118bceef9a216429d3ba5e6c85413a3adefd2
Author: Sheng Yang <sheng@yasker.org>
Date:   Thu Nov 8 17:14:49 2018 -0800

    Longhorn v0.3.2-rc2 release

Sync with Longhorn Manager

	commit 84a789aa73369ce7af52d0a6b0cd6e1e53683eaf
	Author: Sheng Yang <sheng@yasker.org>
	Date:   Wed Nov 7 20:25:06 2018 -0800

	    Longhorn v0.3.2-rc1 release

Longhorn v0.3.1 release

1. Fixed a critical NPE during the upgrade to v0.3.0 release
2. Now reboot a node with attached volume would result in volume automatically reattach to the node.
3. The new Flexvolume automatic detection mechanism should simply the deployment process.

deploy: Reset the FLEXVOLUME_DIR to empty by default

To enable auto detection.