Implement TempDir

Cherry-pick cl/185568469

TEST=acloud create --build_target gce_x86_phone-userdebug_fastbuild3c_linux
--build_id 3744001 --config_file ~/acloud.config
--serial_log /tmp/mylog.tar.gz -vv
Observed temp dir is created and deleted

Merged-In: I6838c26d4b0cefa6d1e999412205728e4be912ce
Change-Id: I6838c26d4b0cefa6d1e999412205728e4be912ce
2 files changed