Replace : in hexdump with " " (two spaces)

src/transport.c

@@ -90,7 +90,9 @@ debugdump(LIBSSH2_SESSION * session,
                 buffer[used++] = ' ';
             }
 
-            buffer[used++] = (c == (width/2)-1) ? ':' : ' ';
+            buffer[used++] = ' ';
+            if ((width/2) - 1 == c)
+                buffer[used++] = ' ';
         }
 
         buffer[used++] = ':';