package/blktrace: fix CVE-2018-10689

blktrace (aka Block IO Tracing) 1.2.0, as used with the Linux kernel and
Android, has a buffer overflow in the dev_map_read function in
btt/devmap.c because the device and devno arrays are too small, as
demonstrated by an invalid free when using the btt program with a
crafted file.

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>