'policy' should be required in server_group_create

The 'policies' param is a required param in nova api now.
So, we also need to change it in cli.

After the modification, the 'policy' param will be required now,
and the old '--policy' style will still be available.

Change-Id: I97921eef0f635c8d50a04bbdaf3ef4f1bfaa3e9d
Closes-Bug: #1323909
Look for all accessible flavors by default, not just public ones

The Nova server will restrict unprivileged user accounts to just
public images, while allowing administrator accounts access to
all. The Nova client shouldn't force the flavor name lookup to
be restricted to just public images, since that breaks the ability
to the flavor name when booting an instance

Fixes bug #1327212

Change-Id: I949aec52660242249b8cba51d77bfdc1acaf31d2
Merge "Look for all accessible flavors by default, not just public ones"
add disk bus and device type to volume attach

This change adds the optional parameters: disk bus and device type
to the volume-attach command for the V3 API.

DocImpact
Closes-Bug: #1303875

Change-Id: I4fd07726887d08e5b669139b559bdb2c2d21826e
Merge "'policy' should be required in server_group_create"