每次apt-get尝试处理 shared-mime-info 的触发器时，它都会报告如下警告：
...
Processing triggers for shared-mime-info...
Unknown media type in type 'all/all'
Unknown media type in type 'all/allfiles'
Unknown media type in type 'uri/mms'
Unknown media type in type 'uri/mmst'
Unknown media type in type 'uri/mmsu'
Unknown media type in type 'uri/pnm'
Unknown media type in type 'uri/rtspt'
Unknown media type in type 'uri/rtspu'
Unknown media type in type 'interface/x-winamp-skin'
我已经检查过/usr/share/mime-info但没有看到其中任何一个：
/usr/share/mime-info$ grep 'url/rtspu' *
(Got nothing)
那么，如何清理我的系统，使其不报告这些未知的媒体类型？
aptitude ×1