openstack: add an empty “exclude” file
opentstack-compute: fix the package name on CentOS
minor: indent code

replace \t with 4 spaces
makefile: use simplified targets

use the “foo” alias target instead of the “$(INST)/foo.done”. This
remove a bit of complexity for the same result.
openstack-compute: packages is an associative array

declare packages as an associative array otherwise the ${foo["key"]}
syntax won't work and only returns the last last value (rpm in this
case)
minor: drop a double space in a message string
makefile: a variable to specify the target to test

This patch add a global variable called TEST_TARGET to pass the
name of the target to test with “make test”. This allow ones to
run command like:

    make test TEST_TARGET=openstack-compute

The default behavior is still to use “mysql” like before.
init: avoid the dependency on bash

sh -c "foo" is available in POSIX sh like dash. There is no need
to depend on bash directly.