git-svn: Fix discarding of extra parents from svn:mergeinfo

If parent J is an ancestor of parent I, then parent J should be
discarded, not I.

Note that J is an ancestor of I if and only if rev-list I..J is emtpy,
which is what we are testing here.

Signed-off-by: Tuomas Suutari <tuomas.suutari@gmail.com>
Acked-by: Eric Wong <normalperson@yhbt.net>

git-svn.perl

@@ -3273,7 +3273,7 @@ sub find_extra_svn_parents {
 					"$new_parents[$i]..$new_parents[$j]",
 				       );
 				if ( !$revs ) {
-					undef($new_parents[$i]);
+					undef($new_parents[$j]);
 				}
 			}
 		}

t/t9151-svn-mergeinfo.sh

@@ -33,7 +33,7 @@ test_expect_success 'svn non-merge merge commits did not become git merge commit
 	[ -z "$bad_non_merges" ]
 	'
 
-test_expect_failure 'commit made to merged branch is reachable from the merge' '
+test_expect_success 'commit made to merged branch is reachable from the merge' '
 	before_commit=$(git rev-list --all --grep="trunk commit before merging trunk to b2")
 	merge_commit=$(git rev-list --all --grep="Merge trunk to b2")
 	not_reachable=$(git rev-list -1 $before_commit --not $merge_commit)