Fix trailing / when downloading stage2 image

In Dracut the URL concatenation from .treeinfo could also point you to
directory above by `..`. However, if the `inst.repo=` argument was
set with trailing `/` it will create URL which is not supported by curl.

Supported:
`os/../BaseOS/`
Unsupported by curl:
`os//../BaseOS/`

Remove the trailing `/` to avoid this issue.

Resolves: RHEL-48821

dracut/anaconda-lib.sh

@@ -112,6 +112,10 @@ anaconda_net_root() {
     local repo="$1"
     info "anaconda: fetching stage2 from $repo"
 
+    # Remove last `/` from repo to enable cunstructs like ...os/../BaseOS/image/install.img
+    # Otherwise curl will fail to work with `...os//../BaseOS...`
+    repo=${repo%/}
+
     # Try to get the local path to stage2 from treeinfo.
     treeinfo=$(fetch_url "$repo/.treeinfo" 2> /tmp/treeinfo_err) && \
         stage2=$(config_get stage2 mainimage < "$treeinfo")