HFX-1078: [SCTX-1635] Handle storage exception while unplugging VBD.

Signed-off-by: Siddharth Vinothkumar <siddharth.vinothkumar@citrix.com>
CA-130161: Revert "CA-126097: Block clone of live VDIs"

Disks attached to a checkpoint look like they're live, so blocking clone
of live VDIs broke checkpoint revert.

This reverts commit a8aece189b38095c74a6e3b0aee3d8d255e42248.
CA-130161: Fix unit tests to test new behaviour

We've re-enabled clone of live VDIs, so the test needs to check this
instead of expecting failure.

Asserting whether a VDI can be cloned checks whether the backend
supports VDI_CLONE, so register the dummy SR with a dummy backend which
has a sensible set of features.

Signed-off-by: John Else <john.else@citrix.com>
Merge pull request #1676 from johnelse/ca-130161

CA-130161: Re-enable clone of live VDIs
CA-129089: Disable global login via slave hosts

Signed-off-by: Zheng Li <dev@zheng.li>
Merge pull request #1677 from zli/xenserver/trunk-ring3/CA-129089

CA-129089: Disable global login via slave hosts
Merge pull request #1675 from yunleid/CA-124981

CA-124981: Port the fix of HFX-1078 from clearwater-sp1-lcm to trunk
README: correct links (should be xenproject.org, not xen.org)

Signed-off-by: David Scott <dave.scott@citrix.com>
README: don't use "XCP" any more; don't use opam; point people at xenserver-core

The XCP story is mostly historical and quite confusing.
The opam build instructions don't work but the xenserver-core ones
are quite good.

Signed-off-by: David Scott <dave.scott@citrix.com>
Add comments explaining xencenter_min_verstring and xencenter_max_verstring
Merge pull request #1680 from djs55/correct-list-address

Update the very old README
Merge pull request #1681 from stephen-turner/patch-1

Add comments explaining xencenter_min_verstring and xencenter_max_verstring
Merge pull request #1673 from robhoes/master

Update API versioning in datamodel to be consistent with CW