Apply double quotes and period punctuation uniformly.

Signed-off-by: Wainer dos Santos Moschetta <wainersm@redhat.com>
Message-Id: <20190321212528.6100-1-wainersm@redhat.com>
Reviewed-by: Fam Zheng <fam@euphon.net>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>