Fix formatter variable referenced before assignment

[FabioRosado]

Description

Moved formatter = logging.Formatter("%(levelname)s %(name)s: %(message)s") line outside try/except block. Removed try/except and added a suppress if KeyError is raised on config['logging']['extended'].

Note: For some reason black and tox didn't run on my end so I was unabled to check tests before raising the PR

Fixes #1429

Status

READY | UNDER DEVELOPMENT | ON HOLD

Type of change

• Bug fix (non-breaking change which fixes an issue)

How Has This Been Tested?

• Tested bot with extended flag set to true - worked as expected.
• Tested bot without extended flag set - worked as expected.
• Ran Travis - all Green

Checklist:

• I have performed a self-review of my own code
• I have made corresponding changes to the documentation (if applicable)
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes

[codecov]

Codecov Report

Merging #1432 into master will decrease coverage by 0.00%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master    #1432      +/-   ##
==========================================
- Coverage   99.90%   99.90%   -0.01%     
==========================================
  Files          52       52              
  Lines        3059     3058       -1     
==========================================
- Hits         3056     3055       -1     
  Misses          3        3              

Impacted Files	Coverage Δ
opsdroid/logging.py	100.00% <100.00%> (ø)

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[Cadair]

ooh, useful 😁