tests/encryptdecrypt: fix errors that cause passing
tests/encryptdecrypt: fix errors that cause passing

The error trap was cleared when using tpm2_getcap
to verify if command encryptdecrypt was supported.

If it wasn't supported, by checking the grep return
code via $?, then a warning is printed and the test
is skipped.

When tpm2_getcap fails, $? is 1 and the test is reported
as passing, which is incorrect.

Signed-off-by: William Roberts <60148e894dabf0b83bde1d460768794cd453c455@intel.com>

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