Fix -Werror=unused-but-set-variable warnings in gcc 4.6

As warning-as-error was enabled, unused-but-set local variable
breaks the build in gcc 4.6 . This CL add a return code check in
TPM_CMK_ApproveMA after verify authorization.

BUG=None
TEST=emerge tpm-emulator under gcc 4.6 toolchain

Change-Id: I540d0a7b1b5190ab6bb4a2432e87263050ef3bc9
Reviewed-on: https://gerrit.chromium.org/gerrit/12677
Tested-by: Rong Chang <rongchang@chromium.org>
Reviewed-by: Luigi Semenzato <semenzato@chromium.org>
1 file changed