Remove lockf as an ITOOL.

It was added in r152006 to handle serializing access of info/dir when
installing INFO files.  We no longer support INFO files since r276551
though.

Sponsored by:	EMC / Isilon Storage Division

Makefile.inc1

@@ -823,7 +823,7 @@ _zoneinfo=	zic tzsetup
 
 ITOOLS=	[ awk cap_mkdb cat chflags chmod chown cmp cp \
 	date echo egrep find grep id install ${_install-info} \
-	ln lockf make mkdir mtree mv pwd_mkdb \
+	ln make mkdir mtree mv pwd_mkdb \
 	rm sed services_mkdb sh strip sysctl test true uname wc ${_zoneinfo} \
 	${LOCAL_ITOOLS}