Avoid assertion failure when using Host Device

[adriansr]

Passing a device ID of zero (Host device) to FSEventsCopyUUIDForDevice
causes the following assertion failure error to be printed to the logs:

(FSEvents.framework) FSEventsCopyUUIDForDevice(): failed assertion 'dev > 0'

[codecov-io]

Codecov Report

Merging #32 into master will increase coverage by 0.09%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master      #32      +/-   ##
==========================================
+ Coverage   71.18%   71.28%   +0.09%     
==========================================
  Files           3        3              
  Lines         288      289       +1     
==========================================
+ Hits          205      206       +1     
  Misses         61       61              
  Partials       22       22

Impacted Files	Coverage Δ
fsevents.go	79.48% <100%> (+0.53%)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update ed9a50f...27bdb44. Read the comment docs.

[drewwells]

@adriansr sorry nobody has looked at this. Can you please rebase on master and see if the tests pass?

[drewwells]

This github conflict editor is nonsense. Please rebase this branch to get upgraded travis tests for 1.10.

[adriansr]

@drewwells it's rebased now. Thanks for looking at this :)

[patsoffice]

@adriansr this PR does not fix the assertion message. Applying your patch and changing the test to use dev id 0 results in the same error message:

2018-07-17 22:04 fsevents.test[23666] (FSEvents.framework) FSEventsCopyUUIDForDevice(): failed assertion 'dev > 0'

[adriansr]

@patsoffice I clearly have broken something.

It seems on May I sent a different fix and for some reason overwrote this branch. Let me see if I can find the original.

[adriansr]

@patsoffice now it's ok

Have a look at #39 too

[patsoffice]

@adriansr thanks. Fortuntely, I haven't come across the problems you're fixing in #39 (yet).

[adriansr]

Closed in favor of @patsoffice PR #38 which is more complete