.gitattributes: update files not for export

A couple of files no longer exist in the repo and some shouldn’t be
exported.

https://bugzilla.gnome.org/show_bug.cgi?id=779579

.gitattributes

@@ -1,6 +1,5 @@
-/scripts                       export-ignore
-/git.mk                        export-ignore
 /.gitattributes                export-ignore
+/.gitignore                    export-ignore
 /.gitmodules                   export-ignore
 /nautilus.doap                 export-ignore
 /.buildconfig                  export-ignore
@@ -11,3 +10,4 @@
 /data/run-uncrustify.sh        export-ignore
 /data/uncrustify.cfg           export-ignore
 /eel/README.canvas             export-ignore
+/make_release.sh               export-ignore