media: video: Prevent memory leak in VCAP

If a client were to do the following, VCAP would not free the ion
handle:
 -Opened VCAP
 -Start initial configuration
 -Queues buffers
 -Close VCAP without ever calling stream on

Since VCAP was not freeing ion this would cause a memory leak

CRs-Fixed: 423881
Change-Id: I594924d85884aa5e0a647bc52fa9e89e720f4ff6
Signed-off-by: Terence Hampson <thampson@codeaurora.org>