libexec/rc/rc.initdiskless: make tar's path flexible

Summary:
PR:		274977
Reviewed by: rgrimes,imp
Approved by: rgrimes
MFC after:      1 month

libexec/rc/rc.initdiskless

@@ -362,6 +362,8 @@ done
 # so if the cpio archive is present, it prevents the files from dir/
 # from being copied.
 
++PATH=${PATH}:/rescue
+
 for i in ${templates} ; do
     for j in /conf/$i/* ; do
 	subdir=${j##*/}
@@ -376,7 +378,7 @@ for i in ${templates} ; do
 	if [ -f $j ]; then
 	    create_md $subdir
 	    echo "Loading /$subdir from cpio archive $j"
-	    (cd / ; /rescue/tar -xpf $j)
+	    (cd / ; tar -xpf $j)
 	fi
     done
     for j in /conf/$i/*/extract ; do