MDL-50888 antivirus_clamav: Unit tests refactoring.
MDL-50888 antivirus_clamav: Unit tests refactoring.

Due to configurable nature of scanning method selection, unit test needs to
be updated to always point to commadline method. There is no need to write
separate tests for socket scanning method, as the scanning method needs to
be mocked anyway (i.e. will be identical to commandline scanning from test
perspective).

dilawar/moodle