clar: Clear errors on shutdown

tests-clar/clar_helpers.c

@@ -9,6 +9,7 @@ void clar_on_init(void)
 void clar_on_shutdown(void)
 {
 	git_threads_shutdown();
+	giterr_clear();
 }
 
 void cl_git_mkfile(const char *filename, const char *content)