Revert "Add a notion of "physical" sysroot, use for remote writing"

This reverts commit 1eff3e8343. There
are a few issues with it.  It's not a critical thing for now, so
let's ugly up the git history and revisit when we have time to
debug it and add more tests.

Besides the below issue, I noticed that the simple `ostree remote add`
now writes to `/ostree/repo/config` because we *aren't* using the
`--sysroot` argument.

Closes: https://github.com/ostreedev/ostree/issues/901

Closes: #902
Approved by: mike-nguyen

src/libostree/ostree-sysroot.c

@@ -135,8 +135,6 @@ ostree_sysroot_constructed (GObject *object)
   repo_path = g_file_resolve_relative_path (self->path, "ostree/repo");
   self->repo = ostree_repo_new_for_sysroot_path (repo_path, self->path);
   self->repo->is_system = TRUE;
-  /* Hold a weak ref for the remote-add handling */
-  g_weak_ref_init (&self->repo->sysroot, object);
 
   G_OBJECT_CLASS (ostree_sysroot_parent_class)->constructed (object);
 }
@@ -815,26 +813,6 @@ ostree_sysroot_load_if_changed (OstreeSysroot  *self,
                                cancellable, error))
     return FALSE;
 
-  /* Determine whether we're "physical" or not, the first time we initialize */
-  if (!self->loaded)
-    {
-      /* If we have a booted deployment, the sysroot is / and we're definitely
-       * not physical.
-       */
-      if (self->booted_deployment)
-        self->is_physical = FALSE;  /* (the default, but explicit for clarity) */
-      /* Otherwise - check for /sysroot which should only exist in a deployment,
-       * not in ${sysroot} (a metavariable for the real physical root).
-       */
-      else if (fstatat (self->sysroot_fd, "sysroot", &stbuf, 0) < 0)
-        {
-          if (errno != ENOENT)
-            return glnx_throw_errno_prefix (error, "fstatat");
-          self->is_physical = TRUE;
-        }
-      /* Otherwise, the default is FALSE */
-    }
-
   self->bootversion = bootversion;
   self->subbootversion = subbootversion;
   self->deployments = deployments;