commit: Fix memory leak in test suite

tests/commit/commit.c

diff --git a/tests/commit/commit.c b/tests/commit/commit.c
index c82971f..c052cd5 100644
--- a/tests/commit/commit.c
+++ b/tests/commit/commit.c
@@ -72,7 +72,7 @@
 	dummy->raw_message = git__strdup(given);
 	cl_assert_equal_s(expected, git_commit_body(dummy));
 
-	git_commit_free(dummy);
+	git_commit__free(dummy);
 }
 
 void test_commit_commit__summary(void)