add missing header end comments

- ensures a consistent usage in header files
- also add a blank line after the copyright header where missing
- also remove orphan new-lines at the end of some files

src/addrman.h

@@ -3,7 +3,7 @@
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
 #ifndef _BITCOIN_ADDRMAN
-#define _BITCOIN_ADDRMAN 1
+#define _BITCOIN_ADDRMAN
 
 #include "netbase.h"
 #include "protocol.h"
@@ -503,4 +503,4 @@ public:
     }
 };
 
-#endif
+#endif // _BITCOIN_ADDRMAN