Duplicate 'COPYLEFT' entries in legal file classification names in legal.py and classify.py

[Pradeepbeleri]

Problem Description

In ScanCode's legal file detection modules, duplicate entries exist in legal filename tuples:

1. special_names in src/licensedcode/legal.py contains duplicate 'COPYLEFT' entries (line 28 and line 38).
2. LEGAL_STARTS_ENDS in src/summarycode/classify.py contains duplicate 'copyleft' entries (line 23 and line 34).

Proposed Fix

Remove the duplicate 'COPYLEFT' and 'copyleft' entries from src/licensedcode/legal.py and src/summarycode/classify.py.

[Pradeepbeleri]

I'm working on a PR to fix this