cli: Initialize bootc storage before upgrade --check

We had a report of `bootc upgrade --check` failing after
a new install - this was using Anaconda with the legacy
`ostreecontainer` verb that only knows about ostree.

Hoist the image_exists_in_unified_storage() call (which ensures the
bootc storage directory exists via get_ensure_imgstore()) above the
opts.check branch so it runs for both --check and full upgrade paths.

Relates: https://issues.redhat.com/browse/RHEL-153671

Assisted-by: OpenCode (Claude Opus 4)
Signed-off-by: Colin Walters <walters@verbum.org>

Author: cgwalters

crates/lib/src/cli.rs

@@ -1119,6 +1119,11 @@ async fn upgrade(
         return Ok(());
     }
 
+    // Ensure the bootc storage directory is initialized; the --check path
+    // needs this for update_mtime() and the non-check path needs it for
+    // unified pull detection.
+    let use_unified = crate::deploy::image_exists_in_unified_storage(storage, imgref).await?;
+
     if opts.check {
         let ostree_imgref = imgref.clone().into();
         let mut imp =
@@ -1144,9 +1149,6 @@ async fn upgrade(
             }
         }
     } else {
-        // Auto-detect whether to use unified storage based on image presence in bootc storage
-        let use_unified = crate::deploy::image_exists_in_unified_storage(storage, imgref).await?;
-
         let fetched = if use_unified {
             crate::deploy::pull_unified(
                 repo,