test(parity): dest-only excluded entry protected under default --delete

Adds the exclude_protect_dest_only differential and flips --delete-excluded
to parity now that receiver-side rules protect a destination-only excluded
entry like rsync; tally 116/10/31.

tests/integration/test_differential_parity.py

@@ -221,6 +221,10 @@ _CASES = [
     H.Case("delete_excluded", "filters",
            ["-a", "--delete", "--delete-excluded", "--exclude=*.log"],
            seed=seed_delete_excluded, server_args=DELETE, ref="--delete-excluded"),
+    H.Case("exclude_protect_dest_only", "filters",
+           ["-a", "--delete", "--exclude=*.log"],
+           seed=seed_delete_excluded, server_args=DELETE, ci=True,
+           ref="--delete protects a destination-only excluded entry like rsync"),
     H.Case("max_delete", "basic", ["-a", "--delete", "--max-delete=1"],
            seed=seed_max_delete, server_args=DELETE,
            extra_check=max_delete_count_check, compare_tree=False,