Update rcS

My RedPitaya fails to mount /opt because /dev/mmcblk0p1 isn't ready yet. Add a retry with a short delay to catch this.
Merge pull request #11 from simonpw/master

Update rcS to catch SD mount failure
Merge remote-tracking branch 'upstream/master' into dev_mybuild
Nginx: Moved client temp dir to /tmp to fix Nginx starting issues.
Merge branch 'master' into dev_mybuild