Fixes README RST markup
Fixes README RST markup

Converts MD markup to RST.

Change-Id: I7f0690ecf977b97ae4fc5f447720da22adee66cd

pellaeon/bsd-cloudinit,pellaeon/bsd-cloudinit,stackforge/cloudbase-init,ader1990/cloudbase-init,CropCircleSys/bsd-cloudinit,bincentvaret/bsd-cloudinit,openstack/cloudbase-init,whiteear/cloudbase-init,cmin764/cloudbase-init,chialiang-8/cloudbase-init,alexpilotti/cloudbase-init,stefan-caraiman/cloudbase-init