$ sudo apt-get update
$ sudo apt-get install gazebo7-plugin-base 

gazebo7-plugin-base is installed in your system.

Make ensure the gazebo7-plugin-base package were installed using the commands given below,

$ sudo dpkg-query -l | grep gazebo7-plugin-base *

You will get with gazebo7-plugin-base package name, version, architecture and description in a table

gazebo7-plugin-base package basic information: