build.py: add missing spaces

Add missing spaces around operators and spaces after comma.

Signed-off-by: Danny Al-Gaaf <danny.al-gaaf@bisect.de>
core.py: add missing spaces

Add missing spaces around operators and spaces after comma.

Signed-off-by: Danny Al-Gaaf <danny.al-gaaf@bisect.de>
fetch.py: fix "More than one statement on a single line"

Signed-off-by: Danny Al-Gaaf <danny.al-gaaf@bisect.de>
checker.py: "More than one statement on a single line"

Signed-off-by: Danny Al-Gaaf <danny.al-gaaf@bisect.de>
OscConfigParser.py: fix __delitem__

Two issues:
- There is no _find() member in ConfigLineOrder. Use _find_section()
  instead
- Use 'key' instead of 'line' as argument for _find_section() since
  'line' is used before assignment.

Signed-off-by: Danny Al-Gaaf <danny.al-gaaf@bisect.de>
OscConfigParser.py: silence pylint false positive E0702

Signed-off-by: Danny Al-Gaaf <danny.al-gaaf@bisect.de>