MediaLibrary: Set logger before acquiring file lock
MediaLibrary: Set logger before acquiring file lock

File locking will attempt to log on failure (ie: the medialib is already
locked).
As `s_logger` null checks were removed [1], logging before constructing
`MediaLibrary` was dereferencing nullptr.

[1] fc002ae17f9b6544d784f609f3b6872544e5d40c

chouquette/medialibrary,chouquette/medialibrary,chouquette/medialibrary,chouquette/medialibrary