Avatar upload dir filters set 'basedir' and 'baseurl' incorrectly

[boonebgorges]

bp_core_signup_avatar_upload_dir(), xprofile_avatar_upload_dir(), and groups_avatar_upload_dir() all filter 'upload_dir' to provide object-type-specific upload locations for avatars. The settings ultimately used by WP for the uploaded files come from the 'path' and 'subdir' values returned by these functions; 'basedir' and 'baseurl' are not used. However, these values *are* used to generate certain error messages (see eg the end of wp_upload_dir()), and we currently set them incorrectly, so that the error message gives an incorrect path (eg wp-content/uploads/group-avatars/123/group-avatars/123).