Glance API V2 can't recognize parameter 'id'

Based on current implement, API V2 is using **id** in image schema,
but using **image_id** for most of the internal functions as key
word arguments. So user will got a key error if using:

glance --os-image-api-version 2 image-create --id <id>

This patch will map 'id' to 'image_id' in RequestDeserializer and
add an unit test case fo the change.

Closes-Bug: 1366515

Change-Id: I4c72881a7ada728307e806776426b42cf4cf0993
Duplicated image id return 409 instead of 500 in API v2

Based on current code, in API v2 duplicated image id will
return HTTP 500 error instead of 409. This patch fix this
issue and add an unit test case for that.

Closes-Bug: 1366503

Change-Id: Ia6c27f9edffd63619d63013e456072d811daf127
Merge "Glance API V2 can't recognize parameter 'id'"
Merge "Duplicated image id return 409 instead of 500 in API v2"