Remove the lock-file configuration and -X argument to named

The lock-file configuration (both from configuration file and -X
argument to named) has better alternatives nowadays.  Modern process
supervisor should be used to ensure that a single named process is
running on a given configuration.

Alternatively, it's possible to wrap the named with flock(1).

bin/tests/system/masterformat/clean.sh

@@ -34,5 +34,4 @@ rm -f ./ns3/example.db.raw ./ns3/dynamic.db.raw
 rm -f ./baseline.txt ./text.* ./raw.*
 rm -f ./ns1/Ksigned.* ./ns1/dsset-signed. ./ns1/signed.db.signed
 rm -f ./rndc.out
-rm -f ./ns*/named.lock
 rm -f ./ns*/managed-keys.bind*