Remove unused add_sample()

add_sample() has been added since I08c9b6a02bcddd8cab2d066928513b4ae40431ec ,
but we never use this metod over 2 years.
So this patch removes the method for cleanup.

Change-Id: I340d96c27f0e906df5b8a109494920e9cd3b21d1
1 file changed