Remove reference to DSA and rename KM_ALGORITHM_ECDSA.

Change-Id: Ibffddc5c3a5c728182f5ca7f6a76381413fc8645
diff --git a/openssl_utils.cpp b/openssl_utils.cpp
index c8e9b79..4424a4d 100644
--- a/openssl_utils.cpp
+++ b/openssl_utils.cpp
@@ -30,7 +30,7 @@
     switch (algorithm) {
     case KM_ALGORITHM_RSA:
         return EVP_PKEY_RSA;
-    case KM_ALGORITHM_ECDSA:
+    case KM_ALGORITHM_EC:
         return EVP_PKEY_EC;
     default:
         return -1;