install euca2ools for tempest preparation

euca-bundle-image can be run only if euca2ools is installed.
but now it doesn't installed and several tests for EC2 doesn't run.

Change-Id: Ib3824052d5f4155d3cb5c0ef6fe334d44de5153c
diff --git a/lib/tempest b/lib/tempest
index 3f33512..d8692dc 100644
--- a/lib/tempest
+++ b/lib/tempest
@@ -562,6 +562,8 @@
             echo "Prepare aki/ari/ami Images"
             mkdir -p $BOTO_MATERIALS_PATH
             ( #new namespace
+                # euca2ools should be installed to call euca-* commands
+                is_package_installed euca2ools || install_package euca2ools
                 # tenant:demo ; user: demo
                 source $TOP_DIR/accrc/demo/demo
                 euca-bundle-image -r ${CIRROS_ARCH} -i "$kernel" --kernel true -d "$BOTO_MATERIALS_PATH"