fstests.yml: use unique ref

Use the ref for the kdevops commit as the KDEVOPS_HOSTS_PREFIX.
If you are using kdevops to test kernel trees you can use the
same trick as a prefix for your guests with KDEVOPS_HOSTS_PREFIX.

This will ensure your self-hosted runner can run more than one
guest at a time.

Signed-off-by: Luis Chamberlain <[email protected]>

Author: mcgrof

.github/workflows/fstests.yml

@@ -26,7 +26,9 @@ jobs:
 
       - name: Run kdevops make defconfig-repo
         run: |
-          make KDEVOPS_HOSTS_PREFIX="gh" defconfig-xfs_reflink_4k
+          KDEVOPS_TREE_REF="${{ github.event_name == 'pull_request' && github.event.pull_request.head.sha || github.sha }}"
+          SHORT_PREFIX="$(echo ${KDEVOPS_TREE_REF:0:4})"
+          make KDEVOPS_HOSTS_PREFIX="$KDEVOPS_TREE_REF" defconfig-xfs_reflink_4k
 
       - name: Run kdevops make
         run: |