lockdown: initialize local array before use to quiet static analysis

The static code analysis tool "Coverity Scan" pointed the following
details out for further development considerations:

  CID 1486102: Uninitialized scalar variable (UNINIT)
  uninit_use_in_call: Using uninitialized value *temp when calling
                      strlen.

Signed-off-by: Tanya Agarwal <tanyaagarwal25699@gmail.com>
[PM: edit/reformat the description, subject line]
Signed-off-by: Paul Moore <paul@paul-moore.com>