TinMan.py: adjust to oz generate_diskimage size unit changing

In clalancette/oz#310 I'm proposing we
change the unit of the `generate_diskimage` method's size arg
from gibibytes to bytes. This needs adjusting to match that.
Don't merge this unless and until that PR is merged.

Signed-off-by: Adam Williamson <[email protected]>

Author: AdamWill

imagefactory_plugins/TinMan/TinMan.py

@@ -336,7 +336,8 @@ def create_base_image(self, builder, template, parameters):
                 try:
                     disksize=getattr(self.guest, "disksize")
                 except AttributeError:
-                    disksize = 10
+                    # 10 GiB
+                    disksize = 10*1024*1024*1024
                 self.guest.generate_diskimage(size = disksize)
                 # TODO: If we already have a base install reuse it
                 #  subject to some rules about updates to underlying repo