Introduce zalloc() wrapper to initialise malloc'ed memory

Global replace malloc() with zalloc() throughout the code.
Also use bzero(zz, sz) instead of memset(xx, 0, sz)

Signed-off-by: Mark Harvey <markh794@gmail.com>
vtllibrary: Removed unnessessary init of var 'i'

Removed 4 instances of variable being set to 0 but not used.
Improved debug message with drive # being cleaned up.

Signed-off-by: Mark Harvey <markh794@gmail.com>
Makefile: 'q.o' removed deplicate in 'make clean'

Remove duplicate 'q.o' entry in Makefile

Signed-off-by: Mark Harvey <markh794@gmail.com>
Add 'LOCATE 10' define to scsi.h

Signed-off-by: Mark Harvey <markh794@gmail.com>