Use "ObjectDoesNotExist" from model_class

[Anton-Shutik]

Fixes #

File "/home/anton/.virtualenvs/epantry/lib/python3.6/site-packages/rest_framework/serializers.py", line 748, in is_valid
    self._validated_data = self.run_validation(self.initial_data)
File "/home/anton/.virtualenvs/epantry/lib/python3.6/site-packages/rest_framework/serializers.py", line 626, in run_validation
    value = self.to_internal_value(data)
File "/home/anton/.virtualenvs/epantry/lib/python3.6/site-packages/rest_framework/serializers.py", line 665, in to_internal_value
    validated = self.child.run_validation(item)
File "/home/anton/.virtualenvs/epantry/lib/python3.6/site-packages/rest_framework/fields.py", line 535, in run_validation
    value = self.to_internal_value(data)
File "/home/anton/projects/ePantry/epantry/django-rest-framework-json-api/rest_framework_json_api/serializers.py", line 49, in to_internal_value
    except ObjectDoesNotExist:
NameError: name 'ObjectDoesNotExist' is not defined

Description of the Change

Looks like ObjectDoesNotExist is not imported in the module and it fails whenever return self.model_class.objects.get(pk=pk) raises an exception

Checklist

• PR only contains one change (considered splitting up PR)
• unit-test added
• documentation updated
• CHANGELOG.md updated (only for user relevant changes)
• author name in AUTHORS

[codecov]

Codecov Report

Merging #683 into master will increase coverage by 0.01%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master     #683      +/-   ##
==========================================
+ Coverage   95.96%   95.98%   +0.01%     
==========================================
  Files          54       54              
  Lines        2728     2737       +9     
==========================================
+ Hits         2618     2627       +9     
  Misses        110      110

Impacted Files	Coverage Δ
example/tests/test_serializers.py	100% <100%> (ø)	⬆️

---

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 7c6cceb...cbcb6e2. Read the comment docs.

[sliverc]

The change looks good. Could you follow up on the other points on the check list (especially writing a test)? Thanks.

[Anton-Shutik]

@sliverc anymore blockers ?

[sliverc]

Mistakenly pushed the wrong branch when updating the PR with a changelog entry.

Change looks good though so I have opened another PR #690 including these changes.