Check parameter 'marker' before make request to glance
Check parameter 'marker' before make request to glance

fix bug: 1065053

Since glance need parameter 'marker' to be a image-id, can not
be None. check 'marker' before make request to glance.

Change-Id: I7fc063ea74ae3be71e2effdc0b62432ebdd52c27
(cherry picked from commit d23cf2096fe62c1e575e79c4ff0af3f1fb7830ad)

paulmathews/nova,paulmathews/nova,paulmathews/nova