0.9.1rc2 - a couple small bugfixes

[nateraw]

Before submitting

• Was this discussed/approved via a Github issue? (no need for typos and docs improvements)
• Did you read the contributor guideline, Pull Request section?
• Did you make sure to update the docs?
• Did you write any new necessary tests?

What does this PR do?

Fixes bug that's causing our builds to fail on missing progress_bar_metrics attribute of trainer.

Seems to have been caused by this PR.

PR review

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[codecov]

Codecov Report

Merging #205 into master will not change coverage.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##           master     #205   +/-   ##
=======================================
  Coverage   89.23%   89.23%           
=======================================
  Files          74       74           
  Lines        3298     3298           
=======================================
  Hits         2943     2943           
  Misses        355      355           

Flag	Coverage Δ
#unittests	89.23% <100.00%> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
..._bolts/models/self_supervised/moco/moco2_module.py	80.15% <100.00%> (ø)

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[nateraw]

@williamFalcon pls merge first thing in the morning.