Disable dexpreopt for deployagent

platform-tools/deployagent.jar is built incorrectly for userdebug sdk
builds (which the build machines in android-build use). In eng builds
dexpreopt is disable by default, so the file is built correctly.

This change disables dexpreopt for deployagent in all builds, for
consistency.

Bug: 122831369

Test: lunch sdk-eng
Test: make sdk
Change-Id: I370f0536d906690b153f114ba3dd589a14d222d4