Use git show-ref instead of trawling .git/refs/heads.
indent
Fix PL check test broken for MSVC in commit 61ace80e

This commit seems to have been badly underdone :-( The test was only
appropriate for non-MSVC type config_opts. I guess nobody (including me)
has tested 4.12 or 4.13 on MSVC up to now.
Mark Release 4.14