Fix: create missing partition images on demand.

The previous patch introduced a regression where, if the userdata
partition image was not present (e.g. userdata-qemu.img), it was
no longer created at startup, and the emulator would fail to run.

This patch fixes the issue.

As an added bonus, it also fixes -wipe-data to ensure that this
option also clears the cache partition, if any. For some reason
the latter was never properly cleared.

Change-Id: Ic97ffa0468da6a8889d64623efaf05148099311f
2 files changed