Fix create_userrc.sh private key hang

tools/create_userrc.sh hangs in a couple of mv commands now that
private keys are created with mode 400.  mv is prompting to
override the permissions, so let's just -f it all.

Change-Id: I8fbb24da6582edcff741653ffdf8bf683b79851a
Merge "Fix create_userrc.sh private key hang"