security: Move security-related files from ~/.ndnx to ~/.ndn

refs: #1363

Change-Id: Ie9f2fdd794dcdbf9cb95083efd79e468fea52e30
diff --git a/src/security/sec-tpm-file.cpp b/src/security/sec-tpm-file.cpp
index 93d2886..bb2ad0b 100644
--- a/src/security/sec-tpm-file.cpp
+++ b/src/security/sec-tpm-file.cpp
@@ -40,7 +40,7 @@
   Impl(const string& dir)
   {
     if(dir.empty())
-      m_keystorePath = boost::filesystem::path(getenv("HOME")) / ".ndnx" / "ndnsec-tpm-file";
+      m_keystorePath = boost::filesystem::path(getenv("HOME")) / ".ndn" / "ndnsec-tpm-file";
     else
       m_keystorePath = dir;