Add remove_swift class

This class removes swift packages on Ubuntu
nodes before new swift packages are installed or
updated. This is a workaround for the broken swift
packages in 5.0 release that conflicts with other packages
durung the update.

Change-Id: I83fb7f78415309d088a6894a54a57708e8b40b91
Closes-Bug: 1356873
Merge "Add remove_swift class" into stable/5.0