use %% because % is a replacement string character

nova/auth/novarc.template

@@ -1,6 +1,6 @@
 NOVARC=$(readlink -f "${BASH_SOURCE:-${0}}" 2>/dev/null) ||
     NOVARC=$(python -c 'import os,sys; print os.path.abspath(os.path.realpath(sys.argv[1]))' "${BASH_SOURCE:-${0}}")
-NOVA_KEY_DIR=${NOVARC%/*}
+NOVA_KEY_DIR=${NOVARC%%/*}
 export EC2_ACCESS_KEY="%(access)s:%(project)s"
 export EC2_SECRET_KEY="%(secret)s"
 export EC2_URL="%(ec2)s"