builtin/describe: fix memory leak with `--contains=`
When calling `git describe --contains=`, we end up invoking `cmd_name_rev()` with some munged argv array. This array may contain allocated strings and furthermore will likely be modified by the called function. This results in two memory leaks: - First, we leak the array that we use to assemble the arguments. - Second, we leak the allocated strings that we may have put into the array. Fix those leaks by creating a separate copy of the array that we can hand over to `cmd_name_rev()`. This allows us to free all strings contained in the `strvec`, as the original vector will not be modified anymore. Furthermore, free both the `strvec` and the copied array to fix the first memory leak. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>