dvr: Handle symlinks for inotify. (#4702)

dvr: Handle symlinks for inotify. (#4702)

The filenames stored in the dvr/log are not realpath but can
be based on symlinks.

So, we might record in to /media/Videos/user1/show1 but
user1 could be a symlink to /media/Videos-drive2 (rather than
a bind mount).

Since inotify returns realpaths, if means that when we attempt
to update the dvr/log the filenames do not match.

So we now monitor the realpath for the directories and convert
filenames to realpath when doing the compare.

We do not store realpath in the dvr/log since users do not
want symlinks replaced with real paths.

Issue: #4702.