Simplify cheeps args passing into GCE metadata am: fda7014a85

Original change: https://android-review.googlesource.com/c/platform/tools/acloud/+/2051322

Change-Id: I3074bd9db9f9d4cd26953a7b7783cff28b2bb1c3
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>