[RESTRICT AUTOMERGE] StorageManagerService: don't ignore failures to prepare user storage am: ecffe3ecbf

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/17416247

Change-Id: I034fc93d091ee1944a5487e58dd61605bc8e19ad
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>