bitbake-whatchanged: change ending quote to proper period

Pretty sure that trailing quote should be a period; it
appears to work properly.

Signed-off-by: Robert P. J. Day <rpjday@crashcourse.ca>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
(cherry picked from commit 579f9ada)
Signed-off-by: Steve Sakoman <steve@sakoman.com>