lib/common.sh: add 'lock_close'; use it as appropriate.

`lock_close FD` is easier to remember than 'exec FD>&-`; and is especially
easier if FD is a variable (though that isn't actually taken advantage of
here).

This uses Bash 4.1+ `exec {var}>&-`, rather than the clunkier
`eval exec "$var>&-"` that was necessary in older versions of Bash.
Thanks to Dave Reisner for pointing this new bit of syntax out to me
the last time I submitted this (back in 2014, 4.1 had just come out).

1 files changed, 1 insertions, 1 deletions

diff --git a/makechrootpkg.in b/makechrootpkg.in
index 284d444..9970145 100644
--- a/makechrootpkg.in
+++ b/makechrootpkg.in
@@ -103,7 +103,7 @@ create_chroot() {
 		stat_done
 
 		# Drop the read lock again
-		exec 8>&-
+		lock_close 8
 	fi
 
 	# Update mtime