checks for correctly created FIFO and starts filling FIFO before rngd access it

Added a check that /etc/rdcentropyservice exists and is a FIFO else corrects it. 
This in fact makes the mknod in the entropyservice-install.sh redundant : removed it

Reversed the order of the two main commands thus start the ssh and feed the FIFO before we stir entropy using rngd in case FIFO is depleted which otherwise caused the whole thing to stop.