lib/repo: Add OSTREE_REPO_COMMIT_STATE_NORMAL to represent most commits

This allows more explicit handling of commit state in code using
libostree, rather than hard-coding a commit state of 0 for ‘normal’.

Signed-off-by: Philip Withnall <withnall@endlessm.com>

Closes: #1335
Approved by: cgwalters

src/libostree/ostree-repo.h

@@ -540,6 +540,7 @@ gboolean      ostree_repo_load_variant_if_exists (OstreeRepo  *self,
                                                   GError       **error);
 
 typedef enum {
+  OSTREE_REPO_COMMIT_STATE_NORMAL = 0,
   OSTREE_REPO_COMMIT_STATE_PARTIAL = (1 << 0),
 } OstreeRepoCommitState;