Remove useless argument of logging macros

Previously, logging macros (info! warn! error!) accepted integer
argument (data1), that was passed to callback function verbatim. In all
call sites this argument was 0.

With this change, that data1 argument is no longer part of macro
interface, 0 is always passed to callback in internals of these macros.

src/key.rs

@@ -245,7 +245,7 @@ impl Key {
                     file_content_c.as_bytes().len(),
                 )
             } {
-            error!(context, 0, "Cannot write key to {}", to_string(file));
+            error!(context, "Cannot write key to {}", to_string(file));
             false
         } else {
             true