dumpstate: Fix IO Errors during zip writing.

We need to always call FinishEntry, even when the poll times
out for whatever unrelated reason.

Bug: 124089395
Test: manual
Test: adb shell /data/nativetest64/dumpstate_test/dumpstate_test
Test: adb shell /data/nativetest64/dumpstate_smoke_test/dumpstate_smoke_test

Change-Id: I039f3b049042988e5e520771b45d0b511d11c461