Remove the null-termination for Java string compatibility.

1. Also change the keyname delimiter in CertTool.java.
2. Return NOTFOUND if the result.len==0 in the listKeys().
3. Define the keystore states in the class Keystore.
diff --git a/cmds/keystore/netkeystore.c b/cmds/keystore/netkeystore.c
index b0d683c..e45e24f 100644
--- a/cmds/keystore/netkeystore.c
+++ b/cmds/keystore/netkeystore.c
@@ -142,7 +142,7 @@
 static void do_listkeys(LPC_MARSHAL *cmd, LPC_MARSHAL *reply)
 {
     reply->retcode = list_keys((const char*)cmd->data, (char*)reply->data);
-    if (!reply->retcode) reply->len = strlen((char*)reply->data) + 1;
+    if (!reply->retcode) reply->len = strlen((char*)reply->data);
 }
 
 // args of get():