Add ploop in disk_format

"ploop" image format is supported in upstream Glance
https://review.openstack.org/341633

And similar patch has been added in python-openstackclient:
https://review.openstack.org/411405

Co-Authored-By: yuyafei <yu.yafei@zte.com.cn>
Change-Id: I1471224df97cf5fecfe7f02e549855af81c45848
Related-Bug: 1650342

glanceclient/tests/unit/v2/fixtures.py

@@ -168,7 +168,8 @@ schema_fixture = {
                 "raw",
                 "qcow2",
                 "vdi",
-                "iso"
+                "iso",
+                "ploop"
             ],
             "type": [
                 "null",

glanceclient/tests/unit/v2/test_shell_v2.py

@@ -46,7 +46,7 @@ def schema_args(schema_getter, omit=None):
                 'description': 'Format of the container'},
             'disk_format': {
                 'enum': [None, 'ami', 'ari', 'aki', 'vhd', 'vhdx', 'vmdk',
-                         'raw', 'qcow2', 'vdi', 'iso'],
+                         'raw', 'qcow2', 'vdi', 'iso', 'ploop'],
                 'type': 'string',
                 'description': 'Format of the disk'},
             'location': {'type': 'string'},

glanceclient/v1/shell.py

@@ -31,7 +31,7 @@ import glanceclient.v1.images
 
 CONTAINER_FORMATS = 'Acceptable formats: ami, ari, aki, bare, and ovf.'
 DISK_FORMATS = ('Acceptable formats: ami, ari, aki, vhd, vmdk, raw, '
-                'qcow2, vdi, and iso.')
+                'qcow2, vdi, iso, and ploop.')
 DATA_FIELDS = ('location', 'copy_from', 'file')
 
 _bool_strict = functools.partial(strutils.bool_from_string, strict=True)

glanceclient/v2/image_schema.py

@@ -106,7 +106,7 @@ _BASE_SCHEMA = {
         },
         "disk_format": {
             "enum": [None, "ami", "ari", "aki", "vhd", "vhdx", "vmdk", "raw",
-                     "qcow2", "vdi", "iso"],
+                     "qcow2", "vdi", "iso", "ploop"],
             "type": ["null", "string"],
             "description": "Format of the disk"
         },