Fail when image is bigger than the volume

When creating a new volume from a qcow2 image stored in glance, we will
be given the physical size of the image instead of the virtual size.
Most drivers will convert that image to raw after downloading for
resizing it to the requested volume size afterwards.

If the virtual size of the image is bigger than the requested one, the
resulting volume might end up being unusable after the resize even
though the creation went good.

This patch will make the volume creation fail if the virtual size of
the image exceeds the one of the requested volume.

Closes-Bug: #1235358
Change-Id: I254cd9e3acf5d9eb7eb913b37d27a14e97568dec
(cherry picked from commit 6e287c0f2bb7d4994d50f1763f412277e4dac6f7)
Pass the size when fetching image in xenapi driver

In commit 6e287c0f2bb7d4994d50f1763f412277e4dac6f7 the fetch_to_raw
method was changed to accept the volume size so it can fail when the
image doesn't fit in the destination volume. In this commit we also
updated all the volume drivers to pass the volume size to that method so
it could perform the check. The xenapi driver missed that change.

This commit updates the xenapi driver to pass the volume size when
fetching the image to enable the introduced check.

Change-Id: I89bc4b3b1c1e6b06f5c529166cf9ffa1fe600c96
Related-Bug: #1235358
(cherry picked from commit c4db75abddbb72ac5f717f6a9266e078b69206a8)
Merge "Fail when image is bigger than the volume" into stable/havana
Merge "Pass the size when fetching image in xenapi driver" into stable/havana