block-vpc: Don't silently create smaller image than requested (Kevin Wolf)

block-vpc: Don't silently create smaller image than requested (Kevin Wolf)

The algorithm from the VHD specification for CHS calculation silently limits
images to 127 GB which may confuse a user who requested a larger image. Better
output an error message and abort.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
git-svn-id: svn://svn.savannah.nongnu.org/qemu/branches/stable_0_10@7183 c046a42c-6fe2-441c-8c8c-71466251a162