tpm2_verifysignature.c: Fix for tool_rc_from_tpm being overwritten by tool_rc_general_error
tpm2_verifysignature.c: Fix for tool_rc_from_tpm being overwritten by tool_rc_general_error

Signed-off-by: Imran Desai <4c1ed57e03ffb00ef59b57a9e5270749c817bcef@gmail.com>

01org/tpm2.0-tools,01org/tpm2.0-tools,01org/tpm2.0-tools