Downgrade SSHD to 0.9.0-4-g5967cfd

Since there is no official 0.9.1 release of the SSHD yet, the
0.9.0-4-g5967cfd version was built from the 0.9.x branch and uploaded to
the Google cloud storage.

This change reverts the following Gerrit commits:

3d9c70c SSHD: Update to 0.13.0
52e4e0c Bump SSHD Mina version to 2.0.8
3921163 Don't use deprecated PGPPublicKeyRingCollection constructor
13452f4 Bump Bouncycastle version to 1.51
5f7d5a7 Update EncryptedContactStore to not use deprecated/removed methods
f69698c Update SSHD to 0.11.1-atlassian-1
67c38c8 Added global request handlers to SshDaemon
c31e17f Update sshd to 0.11.0
b9c66ea Bump SSHD version to 0.10.1 and enable nio2 backend

The reason for the downgrade (copied from the change 60161):

SSHD release 0.9 is known to be free from exhausting thread pool problem
[1]. Unfortunately 0.9 release suffers from sporadic handshake failures
[2].  The fix cannot be cleanly cherry-picked to 0.9 release. The back
port of this fix [3] is tracked under its own issue [4], was uploaded as
PR for SSHD Mina's GH repository [5] and merged recently [6].

Moreover, 0.9 suffers from "Authenticated with partial success" issue
[7]
that was fixed by [8], [9]; this patch must be applied as well.

This reverts commit dc7318b8eeda15732d4d2865fc5a7a0a68b3be15.

[1] https://issues.apache.org/jira/browse/SSHD-348
[2] https://issues.apache.org/jira/browse/SSHD-330
[3] https://git-wip-us.apache.org/repos/asf?p=mina-sshd.git;a=commit;\
h=2aed686bdb21681a421033c6ee5997e5cd8a9a83
[4] https://issues.apache.org/jira/browse/SSHD-356
[5] https://github.com/apache/mina-sshd/pull/7
[6] https://git-wip-us.apache.org/repos/asf?p=mina-sshd.git;a=commit;\
h=cc7162acf7ca89561ca57a9c68de735f17bf168b
[7] https://issues.apache.org/jira/browse/SSHD-254
[8] https://git-wip-us.apache.org/repos/asf?p=mina-sshd.git;a=commit;\
h=28a8ae258b08c6b41ab64ac25f2331168dc0415a
[9] https://gerrit-review.googlesource.com/51516

Change-Id: I889fb02c2cb1aa5df2cf8dcabace086f5094a914
Update 2.10 release notes

- Add information about bug fixes that were recently cherry-picked from
the master branch.

- Move some bug fixes from the new features section to the bug fixes
section.

- Expand the description of the "Add Me" feature on the change screen.

Change-Id: Ie14bab657f5a4f358489b04d16fd330ee66c2c4b
Disable Git over http when Gerrit is not configured to support http

When http is not defined as a download scheme, it removes the http download
links in the UI but git over http was still working.

Bug: issue 1050
Change-Id: I0da82f75c420ddbc8f35382bb66c0aed4b7dbef3
Revert "SSHD: Prevent double authentication for the same public key"

This reverts commit a5959d2216bee502c70ba7c285b2e3873d69d190.

This revert is necessary because of downgrade to the SSHD 0.9.0.

Change-Id: Ia41ad2d9a713ddd515bc383923844227b676070f
Merge branch 'stable-2.9' into stable-2.10

* stable-2.9:
  Downgrade SSHD to 0.9.0-4-g5967cfd

Change-Id: I8648d2abb6eb70638deedca6e394d00394bdb9f0
Merge "Update 2.10 release notes" into stable-2.10
Merge "Revert "SSHD: Prevent double authentication for the same public key"" into stable-2.10
Merge "Merge branch 'stable-2.9' into stable-2.10" into stable-2.10
Update version to 2.10-rc1

Change-Id: Ia5ed1dd73dbfbbfc1330c8af7ddbd3bdf1be27aa
Merge "Disable Git over http when Gerrit is not configured to support http" into stable-2.10
Set version to 2.10-SNAPSHOT

Change-Id: I7a051ebca6d5d989fe8c5b12e84d9974ce4dcb1d