#210 Critical section leak in ewf.c

[Anton Kukoba]

using free() to deallocate memory allocated by tsk_img_malloc() causes critical section leak, because tsk_deinit_lock(&(imgInfo->cache_lock)); is never called. I suggest to replace free() by tsk_img_free() where necessary.
Here's my patch:
https://github.com/sleuthkit/sleuthkit/pull/221