remove the old style as it makes little sense to mention here anymore

HACKING

@@ -20,13 +20,3 @@ libssh2 source code style guide:
  - use braces even for single-statement blocks
  
  - keep source lines shorter than 80 columns
-
-------------
-
- Older libssh2 code that still hasn't quite transitioned to the above
- mentioned style, used a different style:
-
- - indented with tabs (only)
-
- - no line length limits
-