Adding inotify watch every time before polling

Inotify watch will stop watching if we updating the file by moving
from another one. So we need to re-add the watch when noticing a
update.

Test: build and run on host, switching garage mode on and off multiple
times.

Bug: 191206914
Change-Id: Iaad71757799d65751fb8bc22a1c528f9b639ef9f
Merged-In: Iaad71757799d65751fb8bc22a1c528f9b639ef9f
(cherry picked from commit 940be06bf03616a851200fccdb873eea4fdb2136)