Fix read() return value in DownloadStream
Fix read() return value in DownloadStream

mongodb/mongo-perl-driver,xdg/mongo-perl-driver,xdg/mongo-perl-driver,dagolden/mongo-perl-driver,dagolden/mongo-perl-driver,dagolden/mongo-perl-driver,xdg/mongo-perl-driver,mongodb/mongo-perl-driver,dagolden/mongo-perl-driver,mongodb/mongo-perl-driver