patchFix memory leak in git_connect with CONNECT_DIAG_URL

diff --git a/connect.c b/connect.c
index c53f3f1..dccf673 100644
--- a/connect.c
+++ b/connect.c
@@ -755,6 +755,7 @@ struct child_process *git_connect(int fd[2], const char *url,
 				free(hostandport);
 				free(path);
 				free(conn);
+				strbuf_release(&cmd);
 				return NULL;
 			}