Re-instate MBEDTLS_PKCS1_V15 unset

Signed-off-by: Ben Taylor <ben.taylor@linaro.org>
diff --git a/tests/scripts/components-configuration-crypto.sh b/tests/scripts/components-configuration-crypto.sh
index 05c4806..f0c217b 100644
--- a/tests/scripts/components-configuration-crypto.sh
+++ b/tests/scripts/components-configuration-crypto.sh
@@ -1492,6 +1492,7 @@
     scripts/config.py crypto
 
     # Remove RSA support and its dependencies
+    scripts/config.py unset MBEDTLS_PKCS1_V15
     scripts/config.py unset MBEDTLS_KEY_EXCHANGE_ECDHE_RSA_ENABLED
     scripts/config.py unset MBEDTLS_X509_RSASSA_PSS_SUPPORT