miner-fs: Add comments to #endifs

So it is easier to follow the #if condition
miner-fs: Minor code style fixes
tests: Unset TZ if it wasn't set previously
tests: Ensure the "no offset" time test has truly no offsets

If no UTC relation is set to the date, the computer timezone is
picked, which may obviously differ from UTC.
libtracker-data: Fix possible double removal of GIOChannel watch sources

If some channel watch functions returns FALSE, don't attempt to remove the
source again on process_context_destroy(). Also, don't leak stdout_channel.
This fixes critical warnings during make check on the tracker-backup test.
Release 0.17.0