app: Drop unused variables

Looks like `clang` got smarter in f29. It's now finding more unused
variables than before. \o/

Closes: #1787
Approved by: cgwalters

src/app/rpmostree-compose-builtin-rojig.c

@@ -150,7 +150,6 @@ install_packages (RpmOstreeRojigCompose  *self,
   /* For unified core, we have a pkgcache repo. This may be auto-created under
    * the workdir, or live explicitly in the dir for --cache.
    */
-  glnx_autofd int host_rootfs_dfd = -1;
   self->pkgcache_repo = ostree_repo_create_at (self->cachedir_dfd, "pkgcache-repo",
                                                OSTREE_REPO_MODE_BARE_USER, NULL,
                                                cancellable, error);

src/app/rpmostree-compose-builtin-tree.c

@@ -1037,7 +1037,6 @@ impl_commit_tree (RpmOstreeTreeComposeContext *self,
   g_autoptr(GVariant) new_commit = NULL;
   if (!ostree_repo_load_commit (self->repo, new_revision, &new_commit, NULL, error))
     return FALSE;
-  g_autoptr(GVariant) new_commit_inline_meta = g_variant_get_child_value (new_commit, 0);
 
   /* --write-commitid-to overrides writing the ref */
   if (self->ref && !opt_write_commitid_to)

src/libpriv/rpmostree-core.c

@@ -3436,7 +3436,6 @@ apply_rpmfi_overrides (RpmOstreeContext *self,
       if (fn_canonical)
         fn = fn_canonical;
 
-      g_autofree char *modified_fn = NULL;  /* May be used to override fn */
       /* /run and /var paths have already been translated to tmpfiles during
        * unpacking */
       if (g_str_has_prefix (fn, "run/") ||