Fixes a panic in dry-run when using external labels. (#2075)
Fixes a panic in dry-run when using external labels. (#2075)

Fixes #1972.

Signed-off-by: Cyril Tovena <1f3b43b4f8eb8a957255fd6382cb431f49248e69@gmail.com>
grafana/loki,grafana/loki,grafana/loki,grafana/loki,grafana/loki,grafana/loki