eCryptfs: decrypt_pki_encrypted_session_key(): remove kfree() redundant null check

smatch analysis:

fs/ecryptfs/keystore.c:1206 decrypt_pki_encrypted_session_key() info:
 redundant null check on msg calling kfree()

Cc: Dustin Kirkland <dustin.kirkland@gazzang.com>
Cc: ecryptfs@vger.kernel.org
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>
Signed-off-by: Tyler Hicks <tyhicks@canonical.com>

fs/ecryptfs/keystore.c

@@ -1202,8 +1202,7 @@ decrypt_pki_encrypted_session_key(struct ecryptfs_auth_tok *auth_tok,
 				  crypt_stat->key_size);
 	}
 out:
-	if (msg)
-		kfree(msg);
+	kfree(msg);
 	return rc;
 }