Don't package /var/db/locate.database

... or install an empty file.

The locate database is a mutable working file, and unsuitable to be
managed by pkg(8).  locate(1) copes gracefully with the absence of
this file.  Running /etc/periodic/weekly/310.locate will create the
locate database with the correct ownership and permissions.

Having the locate.database file as part of the FreeBSD-runtime package
means it gets zeroed if ever that package gets updated, which is
excessive, given that updating packages will typically only change a
relatively small number of the _filenames_ on the system -- unlike the
file contents.  Plus it always causes it to flag as modified when
verifying checksums, but /var/db/locate.database is expected to be
modified by the user.

MFC after:	1 week
Reviewed by:	manu
Differential Revision:	https://reviews.freebsd.org/D45384

etc/Makefile

@@ -88,10 +88,6 @@ distribution:
 .if ${MK_SENDMAIL} != "no"
 	cd ${.CURDIR}/mail; ${INSTALL} -o ${BINOWN} -g ${BINGRP} -m 644 \
 		-T "package=sendmail" ${ETCMAIL_SENDMAIL} ${DESTDIR}/etc/mail
-.endif
-.if ${MK_LOCATE} != "no"
-	${INSTALL} -o nobody -g ${BINGRP} -m 644 -T "package=runtime"\
-	    /dev/null ${DESTDIR}/var/db/locate.database
 .endif
 	cd ${.CURDIR}/..; ${INSTALL} -o ${BINOWN} -g ${BINGRP} -m 444 \
 		-T "package=runtime" ${FREEBSD} ${DESTDIR}/