FreeBSD/src d614ded (r345318)usr.bin/lockf lockf.c

lockf(1): return EX_UNAVAILABLE if -n is used and the lock file does not
exist

Apply EX_UNAVAILABLE patch part from PR 170775 to match the documentation.

Checked with a command from PR 210770:
lockf -n /tmp/doesnotexist echo; echo $?

PR:             210770
MFC after:      1 week
DeltaFile
+2-0usr.bin/lockf/lockf.c
+2-01 files

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