[fix] EC key sign/verify (#193)

Author: kares

src/main/java/org/jruby/ext/openssl/PKeyEC.java

@@ -220,7 +220,7 @@ public PKeyEC(Ruby runtime, RubyClass type) {
     public PrivateKey getPrivateKey() { return privateKey; }
 
     @Override
-    public String getAlgorithm() { return "EC"; }
+    public String getAlgorithm() { return "ECDSA"; }
 
     @JRubyMethod(rest = true, visibility = Visibility.PRIVATE)
     public IRubyObject initialize(final ThreadContext context, final IRubyObject[] args, Block block) {