Add "-r $RANDFILE" where it is missing

Add "-r $RANDFILE" where it is missing

If the path to the source of random data is not passed explicitly to
dnssec-keygen or dnssec-signzone and the --with-randomdev compile-time
switch is not used, the aforementioned utilities will hang if the
default source of random data (/dev/random) runs out of entropy.  Use
"-r $RANDFILE" to prevent that from happening in affected system tests.