CommandUtil: Fix NULL dereference bug.
CommandUtil: Fix NULL dereference bug.

Funny enough the check for NULL is present but only after the
dereference. Pervasive use of the SYS_CONTEXT macro is insidious.

Signed-off-by: Philip Tricca <fd418754d31777cf39b16b99b0350486ab840079@intel.com>

tpm2-software/tpm2-tss,01org/tpm2-tss,tpm2-software/tpm2-tss,01org/TPM2.0-TSS,tpm2-software/tpm2-tss,01org/TPM2.0-TSS,01org/tpm2-tss,01org/TPM2.0-TSS,01org/tpm2-tss,01org/TPM2.0-TSS