rename logshipper -> logtap

- it matches the executable name
- it doesn't ship anything anyway, it's just plumbing

pkgs/default.nix

@@ -100,7 +100,7 @@ in
   levitate = callPackage ./levitate { };
   libubootenv = callPackage ./libubootenv { };
   linotify = callPackage ./linotify { };
-  logshipper = callPackage ./logshipper { };
+  logtap = callPackage ./logtap { };
   lualinux = callPackage ./lualinux { };
 
   # we need to build real lzma instead of using xz, because the lzma