Merge "Adding wait for a device file before mount" am: bd742a15 am:...

Merge "Adding wait for a device file before mount" am: bd742a15 am: d5401ddf am: 39800452 am: b9fc4794

Original change: https://android-review.googlesource.com/c/platform/system/core/+/1322740

Change-Id: I87154d64084cf30626d1eca04880b283b742a9b8