VMware: remove duplicate _fake_create_session code

This patch pulls the _fake_create_session method out so it can be reused
across tests rather than duplicated it.

Change-Id: Ie3979a84568571b2f1f63e01c6c5fb6966f0333a
Closes-bug: 1312472
VMware: remove unneeded code

Change-Id: Ia5ef0e48227ad81407c452a4f57677f2a3b7848c
Create the image mappings BDMs earlier in the boot

Refactor the processing of BDMs defined in the image (either as a block
device mapping in the properties or mappings of blank devices) and move
it to the same method where the rest of BDMs are processed.

Partial-bug: #1297325
Change-Id: Ida0ddb6efcb0014890762df000eaea679f9b1d7b
Merge "VMware: remove duplicate _fake_create_session code"
Merge "VMware: remove unneeded code"
Merge "Create the image mappings BDMs earlier in the boot"