fix syntax error in readme
fix syntax error in readme

Fix a restructuredtext syntax error in README.rst. Without this
change, it will not be possible to release senlin-dashboard.

Change-Id: I482754f9c697762a0531b6031a5e81a4582d5bc4
Signed-off-by: Doug Hellmann <0798ebecfb7bc4dfb9d0445c2fa030eb64e1fa1c@doughellmann.com>

stackforge/senlin-dashboard,stackforge/senlin-dashboard,openstack/senlin-dashboard,stackforge/senlin-dashboard,openstack/senlin-dashboard,openstack/senlin-dashboard,openstack/senlin-dashboard