Evidence store may leak resource

[goolAdapter]

there is a leak, iter need defer iter.Close().

tendermint/evidence/store.go

Lines 100 to 101 in 0c9c329

	iter := dbm.IteratePrefix(store.db, []byte(prefixKey))
	for ; iter.Valid(); iter.Next() {

by the way,

tendermint/evidence/store.go

Lines 82 to 85 in 0c9c329

	l2 := make([]types.Evidence, len(l))
	for i := range l {
	l2[i] = l[len(l)-1-i]
	}

should replace with reversing trick to eliminate temp slice.

for i := len(a)/2-1; i >= 0; i-- {
	opp := len(a)-1-i
	a[i], a[opp] = a[opp], a[i]
}

I'll make a PR for this issue.

[melekes]

Merged to develop. Thanks!