Removing an extra installd call.

There's no need to try to create the oat dir over and over again, especially since it involve an extra installd call. Creating it (if supported) on the fly during the dexopt call.

Change-Id: Id87165e5daaa4b0f1df8d6e985edb52fedc7db47
Test: refactoring CL. Existing unit tests still pass.