scripts/rsatoc: fix printing of error message, if environment variable doen't contain a path ...

Fixes: 128ad3cbe043 ("scripts: Add rsatoc tool")
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

scripts: Add rsatoc tool ...

The rsatoc tool converts rsa public keys into C structs suitable to
compile with barebox. Most of the openssl rsa related stuff has been
taken from the U-Boot mkimage tool.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>