Update get images tests

*Updated get_images module
-Updated tests due to behavior, fixture and config changes
-Moved image creation to setup class
-Updated test steps
*Updated get_images_positive module
-Updated tests due to behavior, fixture and config changes
-Added compare_images_glance_nova test
-Removed check for specific image
-Removed server build validation
-Updated test steps
*Updated get_images_filter module:
-Updated tests due to behavior, fixture and config changes
-Updated test steps
*Updated get_images_sort module
-Updated tests due to behavior, fixture and config changes

Change-Id: If46d6804912f5544b50ff56dbf336d603a045ed1
Merge "Update get images tests"