hdt: Fixing memory leak in cli

The dynamically alloc'd string to protect from strtok modification
has not been free'd on start_auto_mode() function.

This patch insure the free is done properly.
acpi: Removing memset of buffer

There is no need to memset the buffer since the strncat will end the
string with a \0. The memset was also almost wrong as doing a sizeof()
on a char * could return 1 if buff was malloc'ed.

We had chance as all the current calls are done with static buffers.

Removing this memset call will make things clearer but also will prevent
compilation warnings like :

com32/gpllib/acpi/acpi.c:38:29: warning: argument to ‘sizeof’ in ‘memset’ call is the same expression as the
destination; did you mean to provide an explicit length? [-Wsizeof-pointer-memaccess]
     memset(buffer, 0, sizeof(buffer));