Use the original property for debug and loglevel

[artonge]

OC.debug declaration: https://github.com/nextcloud/server/blob/65b1c8b6e83b8a31a78b7ba18faeeb22c33258c2/core/src/OC/debug.js#L23-L26
OC.config declaration: https://github.com/nextcloud/server/blob/65b1c8b6e83b8a31a78b7ba18faeeb22c33258c2/core/src/OC/config.js#L23-L26

[codecov]

Codecov Report

Merging #550 (e110dec) into master (c8a245e) will not change coverage.
The diff coverage is 100.00%.

❗ Current head e110dec differs from pull request most recent head e89eb01. Consider uploading reports for the commit e89eb01 to get more accurate results

@@            Coverage Diff            @@
##            master      #550   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files            4         4           
  Lines           74        74           
  Branches        13        13           
=========================================
  Hits            74        74           

Files Changed	Coverage Δ
lib/LoggerBuilder.ts	100.00% <100.00%> (ø)