Reimplement case_insensitive_strncmp
Reimplement case_insensitive_strncmp

This patch replaces the old implementation of the posix strncasecmp
substitute, with a more straight forward implementation.

This also removes the access to unitialized memory in the old
implementation.

Signed-off-by: Peter Huewe <014f16385c5a8ff1646b588a3d5169b595c0f10e@gmx.de>

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