divide (rounded up) the amount of energy lost.
When a monster's attack is warded off the energy consumed is half that of what the attack would normally have taken, a change from it not taking any energy at all.
git-svn-id: https://crawl-ref.svn.sourceforge.net/svnroot/crawl-ref/trunk@5249 c06c8d41-db1a-0410-9941-cceddc491573
U5E476KITX52LCQEDW7OYSEJJS3B7624LHAUFENVMNZM76OAFJ6QC
22MF6OUN62WDBJR5QFNJTKU7Q5TIQ76XWCEIRBFWAZDMZUSKJGCAC
FCZSQBKDNMJZRJS2LWQQWLUFGOXSKXDJZQIHC7L5S7HXCXQPOMMAC
TVC7W7C2XKBQSD2IJFMWFVGXZAOD4EUOW43NAQTOF5KFMAUOJABQC
K2CS6TCX2NDVL2ASEHGP4J4K4IJ6FP3ANNKTSIWVG43HPYSBX6ZQC
QDTVLBRGHDTRUVT7I3O72K6TMOYAUSAJBZUHGOEFU2RKJNUPWZSQC
5XSXMOBGXFLTIQE6WDXWWFVDOTUPZSIQ2FWT3YI5QMVU6D76IUYQC
OP6CTAKWCAU64JXQ3USQYR5E5IFHQHNCACII5UMVRXUTZXJQOAZAC