CA-95060: Keep trying xenopsd->SMAPI calls until they stop throwing ECONNREFUSED.

If xapi is not running, xenopsd should wait indefinitely for it to
return when trying to make SMAPI calls.

Signed-off-by: John Else <john.else@citrix.com>
CA-95060: Move exception No_storage_plugin_for_sr to storage_interface.ml

This makes it easier to catch for SMAPI clients, since it no longer gets
wrapped in a Storage_interface.Internal_error.

Signed-off-by: John Else <john.else@citrix.com>
Whitespace: Xenops_server_xen.Storage.dp_destroy

Signed-off-by: John Else <john.else@citrix.com>
CA-95060: Ignore Storage_interface.No_storage_plugin_for_sr when calling DP.destroy from xenops.

Signed-off-by: John Else <john.else@citrix.com>
Merge pull request #939 from johnelse/ca-95060-clearwater

CLEARWATER: CA-95060 - If a VM shuts down on a slave when xapi is not running, its disks are not deactivated when xapi starts up again
Merge pull request #938 from mcclurmc/ca95078-revert-for-clearwater

Revert commit 3d2f4b37c3 which broke build clearwater-61910
Whitespace: Xapi_pv_drivers_version.of_drivers_version.

$ camlp4o -printer o -no_comments ocaml/xapi/xapi_pv_driver_version.ml | md5sum
5605b59b4dae1e43796c0b158ae99dcd  -
$ git checkout HEAD^
$ camlp4o -printer o -no_comments ocaml/xapi/xapi_pv_driver_version.ml | md5sum
5605b59b4dae1e43796c0b158ae99dcd  -

Signed-off-by: John Else <john.else@citrix.com>
CA-89023: Fix PV tools OS type detection.

Using the /drivers/xenvbd xenstore key to flag that a guest is Windows
is problematic, since:

1. This key goes away after suspend/resume or migrate, so cannot be
   relied upon to mark PV tools as out of date after a rolling pool upgrade.
2. This key isn't written at all by the Tampa PV drivers.

Instead, we now check that /data/os_distro equals "windows" - this value is
hardcoded in the windows guest agent.

Signed-off-by: John Else <john.else@citrix.com>
Fix typo.

Signed-off-by: John Else <john.else@citrix.com>
Merge pull request #952 from johnelse/ca-89023-clearwater

CLEARWATER: CA-89023: Fix PV tools OS type detection.
CA-94406: reapply fixed commit

Signed-off-by: Mike McClurg <mike.mcclurg@citrix.com>