Exercise cleanup

* Make common steps consistent
* Make comments consistent

aggregates.sh
boot_from_volume.sh
client-args.sh
client-env.sh
euca.sh
floating_ips.sh
sec_groups.sh
swift.sh
volumes.sh

Change-Id: Ib93dcdfdead93c259e3cd184fbc5ccc0a4a87c9a
diff --git a/exercises/sec_groups.sh b/exercises/sec_groups.sh
index fbd9c8e..a33c9c6 100755
--- a/exercises/sec_groups.sh
+++ b/exercises/sec_groups.sh
@@ -2,7 +2,7 @@
 
 # **sec_groups.sh**
 
-# Test security groups via the command line tools that ship with it.
+# Test security groups via the command line
 
 echo "*********************************************************************"
 echo "Begin DevStack Exercise: $0"
@@ -41,7 +41,7 @@
 nova secgroup-list
 
 # Create random name for new sec group and create secgroup of said name
-SEC_GROUP_NAME="sec-group-$(openssl rand -hex 4)"
+SEC_GROUP_NAME="ex-secgroup-$(openssl rand -hex 4)"
 nova secgroup-create $SEC_GROUP_NAME 'a test security group'
 
 # Add some rules to the secgroup
@@ -65,8 +65,10 @@
 for RULE in "${RULES_TO_ADD[@]}"; do
     nova secgroup-delete-rule $SEC_GROUP_NAME tcp $RULE $RULE 0.0.0.0/0
 done
-nova secgroup-delete $SEC_GROUP_NAME
 
+# Delete secgroup
+nova secgroup-delete $SEC_GROUP_NAME || \
+    die "Failure deleting security group $SEC_GROUP_NAME"
 
 set +o xtrace
 echo "*********************************************************************"