fix(update): skips update when nothing to update

[sushantdhiman]

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Description of change

Fixes #7101

[codecov]

Codecov Report

Merging #10248 into master will increase coverage by <.01%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master   #10248      +/-   ##
==========================================
+ Coverage   96.28%   96.28%   +<.01%     
==========================================
  Files          68       68              
  Lines        9795     9797       +2     
==========================================
+ Hits         9431     9433       +2     
  Misses        364      364

Impacted Files	Coverage Δ
lib/model.js	96.77% <100%> (ø)	⬆️

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[zupper]

The same behavior is still observable in 5.7.3. Noticing the below log, where my updatedAt column is aliased to updated in the model definition's options:

2019/04/23 12:12:49 Executing (817790ac-3497-4294-b399-f85c0608cef4): UPDATE `Event` SET `updated`=? WHERE `id` = ?