Currently, `doc/source/_static/cloudkitty.conf.sample` is stored in
the git; however, building the doc overrides it. This is a problem
when building distro packages, as the clean target cannot be written
properly without hacks.
Change-Id: I28fb70e646b000032fb7181a3ffcc0d7097f9dc1
Story: #2010920
Task: #48780