Remove hardcoded version

API clients generally use semantic versioning, not pbr's pre-version facility.
This line causes local package builds to have the wrong version today
(0.0.2.dev.. when 0.0.2 is already released). Furthermore pbr will in future
detect this and error. Removing the line will let pbr automatically manage
versions for you.

Change-Id: Idd75b05c8b9ce93fcb71bc46cf648a3be99e53a0