升级问题
计算升级时出现无法解决的问题：
The package 'unity' is marked for removal but it is in the removal blacklist. This can be caused by: * Upgrading to a pre-release version of Ubuntu * Running the current pre-release version of Ubuntu * Unofficial software packages not provided by Ubuntu If none of this applies, then please report this bug using the command 'ubuntu-bug ubuntu-release-upgrader-core' in a terminal. 我该怎么办？ 我是否需要从黑名单中移除untiy但是如何？
选项1：
update manager -d
选项2：
Step 1: Install Gnome Step 2: Log in Through Gnome Step 3: Uninstall unity using Synaptic Step 4: Try upgrade