REGTEST: ssl: test "set ssl cert" with separate key / crt

This reg-test tests the "set ssl cert" command the same way the
set_ssl_cert.vtc does, but with separate key/crt files and with the
ssl-load-extra-del-ext.

It introduces new key/.crt files that contains the same pair as the
existing .pem.
diff --git a/reg-tests/ssl/ecdsa.key b/reg-tests/ssl/ecdsa.key
new file mode 100644
index 0000000..6eec0ec
--- /dev/null
+++ b/reg-tests/ssl/ecdsa.key
@@ -0,0 +1,6 @@
+-----BEGIN PRIVATE KEY-----
+MIG2AgEAMBAGByqGSM49AgEGBSuBBAAiBIGeMIGbAgEBBDDZMkuztqaUgCAC9/7P
+CsmlC2ac7rWerq5+NKbP0Cz1+mao6+F5Hc8DKNXHgi5GPr2hZANiAAQc00b9lK5L
+sJe8vTfJ79j4uladfzXyadiTGpRB0U7Y3UI7SnqRIgwevMxAhF6/f6PaDp2sp6Ew
+aMGZ5knCxsPqdjJQ7XP7Qxq1blSJMxYWY+ri/TxMMO13yw1xaCxJatM=
+-----END PRIVATE KEY-----