ITS#5810: tweak previous commit - explain backend exclusion

tests/scripts/test044-dynlist

@@ -22,7 +22,7 @@ fi
 
 if test $BACKEND = ldif ; then
 	# dynlist+ldif fails because back-ldif lacks bi_op_compare()
-	echo "Test does not support $BACKEND backend, test skipped"
+	echo "$BACKEND backend unsuitable for dynlist overlay, test skipped"
 	exit 0
 fi
 

tests/scripts/test057-memberof-refint

@@ -28,6 +28,7 @@ if test $REFINT = refintno; then
 fi 
 
 case $BACKEND in bdb | null)
+	# BDB lacks subtree rename, NULL lacks cn=config support
 	echo "Test does not support $BACKEND, test skipped"
 	exit 0
 esac