Return BadRequest for invalid Unicode names

Return BadRequest for invalid Unicode names

If the database fails to insert values due to them
containing Unicode that the database can't support (or other
similar errors that fall under DBDataError), return an
HTTP 400 Bad Request rather than HTTP 500.

this patch give fix for

1. backup-create Creates a volume backup.
2. cgsnapshot-create Creates a cgsnapshot.
3. consisgroup-create Creates a consistency group.
4. encryption-type-create Creates encryption-type
5. qos-create Creates a qos specs.
6. snapshot-create Creates a snapshot.
7. type-create Creates a volume type.
8. update/edit of entities mentioned in step1-7 update/edit name.
 ( is already taken care)

 this patch also fix volume create as is taken care by

 https://review.openstack.org/#/c/266036

 by the new mechanism

Change-Id: I0990fdbcda7ef58331503489a51e7f870683f22b
Closes-bug: #1531400