Move all EC2 cred creation to eucarc

* Remove credential creation from files/keystone_data.sh
* Remove EC2 cert setup from openrc
* Remove sourcing of ec2rc from stackrc
* Collect the above in eucarc
* Allow rc files to be sourced from other directories; based on Chmouel's
  4881 proposal but is simpler and doesn't actually change the directory
* Create S3 endpoint
* Get EC2 and S3 endpoints from Keystone service catalog
* Add EC2 credential checks to exercises/client-env.sh
* exercises/bundle.sh and exercises/euca.sh use eucarc

Updates:
* remove readlink -f to stay bash 3 compatible
* use service catalog
* create S3 endpoint

Fixes bug 949528

Change-Id: I58caea8cecbbd10661779bc2d150d241f4a5822e
diff --git a/stackrc b/stackrc
index a20426b..8df3b83 100644
--- a/stackrc
+++ b/stackrc
@@ -1,3 +1,6 @@
+# Find the other rc files
+RC_DIR=$(cd $(dirname "$BASH_SOURCE") && pwd)
+
 # compute service
 NOVA_REPO=https://github.com/openstack/nova.git
 NOVA_BRANCH=master
@@ -76,12 +79,7 @@
         IMAGE_URLS="http://launchpad.net/cirros/trunk/0.3.0/+download/cirros-0.3.0-x86_64-uec.tar.gz";;
 esac
 
-# use stored ec2 env variables
-if [ -f ./ec2rc ]; then
-    source ./ec2rc
-fi
-
 # allow local overrides of env variables
-if [ -f ./localrc ]; then
-    source ./localrc
+if [ -f $RC_DIR/localrc ]; then
+    source $RC_DIR/localrc
 fi