Reuse exceptions from Oslo

- Remove unused exceptions from novaclient.exceptions
- Reuse exceptions from common code

OpenStack clients which already use exception from common code:
- ironicclient   - I784007f36dd6a63fc4c77e0d0f0f000e05eb792f
- keystoneclient - Iedf4e5d753d4278d81751ba0f55fdef3566b56de
- saharaclient
- tuskarclient   - Iacbf219168fae62d864c6594dd41e0737e848cfa

Similar patches in other clients related to reusing exceptions
from common code:
- cinderclient   - I07f04ba5357e0196fe43b510e1d2fff5afa02faa
- glanceclient   - I9838391cff7e450f08d27668564b02e63259186c

Related to blueprint common-client-library-2

Change-Id: Ia35d65d57a0047f88a609070f8b4c76215cbd3e9
Merge "Reuse exceptions from Oslo"