qcow2: free old snapshots array upon creation of a new one (Uri Lublin)

Don't leak memory

Rebased for qemu tree.

Signed-off-by: Uri Lublin <uril@redhat.com> 
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>



git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@6245 c046a42c-6fe2-441c-8c8c-71466251a162
