index: do not free vectors twice in git_index_free()

git_index_clear() frees index->entries and index->unmerged. No need to
free it once again.

Signed-off-by: Kirill A. Shutemov <kirill@shutemov.name>

src/index.c

@@ -202,8 +202,6 @@ void git_index_free(git_index *index)
 		return;
 
 	git_index_clear(index);
-	git_vector_free(&index->entries);
-	git_vector_free(&index->unmerged);
 
 	free(index->index_file_path);
 	free(index);