diff_print: drop unused OstreeRepo argument

Noticed this while working on diff output somewhere else. I was
initially thinking of making use of this there too, but it's not quite
the right fit and would require a lot of churn.

Closes: #1121
Approved by: cgwalters

src/app/rpmostree-libbuiltin.c

@@ -110,7 +110,7 @@ rpmostree_print_treepkg_diff (OstreeSysroot    *sysroot,
                                cancellable, error))
         return FALSE;
 
-      rpmostree_diff_print (repo, removed, added, modified_old, modified_new);
+      rpmostree_diff_print (removed, added, modified_old, modified_new);
     }
 
   return TRUE;

src/libpriv/rpmostree-util.c

@@ -674,8 +674,7 @@ rpmostree_break_hardlink (int           dfd,
 
 /* Given the result of rpm_ostree_db_diff(), print it. */
 void
-rpmostree_diff_print (OstreeRepo *repo,
-                      GPtrArray *removed,
+rpmostree_diff_print (GPtrArray *removed,
                       GPtrArray *added,
                       GPtrArray *modified_old,
                       GPtrArray *modified_new)

src/libpriv/rpmostree-util.h

@@ -86,8 +86,7 @@ gs_file_get_path_cached (GFile *file)
 
 gboolean rpmostree_stdout_is_journal (void);
 
-void rpmostree_diff_print (OstreeRepo *repo,
-                           GPtrArray *removed,
+void rpmostree_diff_print (GPtrArray *removed,
                            GPtrArray *added,
                            GPtrArray *modified_old,
                            GPtrArray *modified_new);