Mark Nimble driver as unsupported

The Nimble CI has not reported success past our CI required
period.

Checking name: Nimble Storage CI
  first seen: 2016-07-12 18:33:36 (295 days, 22:36:45 old)
  last seen: 2017-02-27 23:42:16 (65 days, 17:28:05 old)
  last success: 2017-02-27 23:42:16 (65 days, 17:28:05 old)
  Job nimble-fc-driver-dsvm-volume 61% success out of 88 comments S=54, F=34
  Job nimble-iscsi-driver-dsvm-volume 36% success out of 131 comments S=48, F=83
      last success: 2017-01-26 20:33:12 (97 days, 20:37:09 old)
Overall success rate: 46% of 250 comments

Per Cinder's non-compliance policy, this patch marks the driver
as unsupported and deprecated and it will be removed in the
next cycle if the issue is not corrected.

Change-Id: Ie068ae8d8fbc224d78118818426e514ba3e100e3

cinder/volume/drivers/nimble.py

@@ -131,6 +131,9 @@ class NimbleBaseVolumeDriver(san.SanDriver):
     # ThirdPartySystems wiki page
     CI_WIKI_NAME = "Nimble_Storage_CI"
 
+    # TODO(smcginnis) Remove driver in Queens if CI issues are not resolved
+    SUPPORTED = False
+
     def __init__(self, *args, **kwargs):
         super(NimbleBaseVolumeDriver, self).__init__(*args, **kwargs)
         self.APIExecutor = None

releasenotes/notes/mark-nimble-deprecated-9f7d1c178b48fa39.yaml

@@ -0,0 +1,13 @@
+---
+upgrade:
+  - |
+    The Nimble driver has been marked as unsupported and is now deprecated.
+    ``enable_unsupported_driver`` will need to be set to ``True`` in
+    the driver's section in cinder.conf to continue to use it.
+deprecations:
+  - |
+    The Nimble driver has been marked as unsupported and is now deprecated.
+    ``enable_unsupported_driver`` will need to be set to ``True`` in
+    the driver's section in cinder.conf to continue to use it. If the
+    support status does not change, they will be removed in the Queens
+    development cycle.