Merge "fastboot: Introduce FASTBOOT_DEVICE alias for ANDROID_SERIAL...

Merge "fastboot: Introduce FASTBOOT_DEVICE alias for ANDROID_SERIAL environment variable" am: 929a665f am: a5d6d550 am: 672482ad

Original change: https://android-review.googlesource.com/c/platform/system/core/+/2621310



Change-Id: I00dac6b4e49566648fcc6c22e21816cef061e797
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>