python-pyasn1 is truly optional since version 2.5.0 and
a31818c285
Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
(cherry picked from commit 78da0a0ea3)
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>