makepkg: do insensitive comparisons of checksums.

This fixes FS#11283 , which was originally reported on the forums :
http://bbs.archlinux.org/viewtopic.php?id=53794

Insensitive comparisons were implicitly made before since md5sum --status was
used for checking. Now that we use openssl and compare checksums manually in
bash, we lost that feature.
This can be easily reintroduced using tr '[A-F]' '[a-f]'

What convinced me to fix it is that the md5 command line tool generates md5sums
in upper case by default :
http://www.fourmilab.ch/md5/

And finally, A-F and a-f are the same in hex and both are used.

Signed-off-by: Xavier Chantry <shiningxc@gmail.com>
Signed-off-by: Dan McGee <dan@archlinux.org>

scripts/makepkg.sh.in

@@ -550,7 +550,9 @@ check_checksums() {
 					fi
 				fi
 
-				if [ "${integrity_sums[$idx]}" = "$(openssl dgst -${integ} "$file" | awk '{print $NF}')" ]; then
+				local expectedsum="$(echo ${integrity_sums[$idx]} | tr '[A-F]' '[a-f]')"
+				local realsum="$(openssl dgst -${integ} "$file" | awk '{print $NF}')"
+				if [ "$expectedsum" = "$realsum" ]; then
 					echo "$(gettext "Passed")" >&2
 				else
 					echo "$(gettext "FAILED")" >&2