Exercises: euca bugfix, output cleanup.
Don't log stderr per-exercise, because stdout is barfy anyway.
Move the state of skip/pass/fail to the end of the exercise run.
diff --git a/exercises/euca.sh b/exercises/euca.sh
index 0d48c93..bf6910d 100755
--- a/exercises/euca.sh
+++ b/exercises/euca.sh
@@ -25,7 +25,7 @@
IMAGE=`euca-describe-images | grep machine | cut -f2`
# launch it
-INSTANCE=`euca-run-instance $IMAGE | grep INSTANCE | cut -f2`
+INSTANCE=`euca-run-instances $IMAGE | grep INSTANCE | cut -f2`
# assure it has booted within a reasonable time
if ! timeout $BOOT_TIMEOUT sh -c "while euca-describe-instances $INSTANCE | grep -q running; do sleep 1; done"; then