AOSP: e2fsdroid: Skip Base FS entries that no longer exist.

AOSP: e2fsdroid: Skip Base FS entries that no longer exist.

Don't reserve blocks in the base map if the file does not exist in the
target image. This can happen if a file is removed or renamed in between
two builds. If the removed file is quite large, skipping it is important
since otherwise it will prevent blocks from being allocated for new files.

Bug: 145316683
Test: e2fsdroid with dynamic partitions
Change-Id: I63a9372c58adeaae3e1235fd92fed78a284ed391
From AOSP commit: 2b6646a3d2a7dd9972275cb829239ae033762da5