security: Moving signInTpm(Data& data, ...) from SecTpm to KeyChain.

The method is no longer a pure virtual method, and sub-classes of SecTpm do not have to implement this one.
Although the method is now a part of KeyChain, but it is still named as signInTpm to be distinguished from the other sign methods of KeyChain.
signInTpm takes the public key name as argument, well sign methods take certificate name as argument.

Change-Id: I6a1546f760a7446341a152bb2f716032f2b7bb58
diff --git a/include/ndn-cpp-dev/security/sec-tpm.hpp b/include/ndn-cpp-dev/security/sec-tpm.hpp
index c6b5328..dd9a55e 100644
--- a/include/ndn-cpp-dev/security/sec-tpm.hpp
+++ b/include/ndn-cpp-dev/security/sec-tpm.hpp
@@ -45,18 +45,16 @@
   getPublicKeyFromTpm(const Name& keyName) = 0;
   
   /**
-   * Fetch the private key for keyName and sign the data, returning a signature Blob.
+   * Fetch the private key for keyName and sign the data, returning a signature block.
    * @param data Pointer to the input byte array.
    * @param dataLength The length of data.
    * @param keyName The name of the signing key.
    * @param digestAlgorithm the digest algorithm.
-   * @return The signature, or a null pointer if signing fails.
+   * @return The signature block.
+   * @throws SecTpm::Error
    */  
   virtual Block
   signInTpm(const uint8_t *data, size_t dataLength, const Name& keyName, DigestAlgorithm digestAlgorithm) = 0;
-
-  virtual void
-  signInTpm(Data &data, const Name& keyName, DigestAlgorithm digestAlgorithm) = 0;
   
   /**
    * Decrypt data.