Tar v doc fix.
Tar r bug ifx.
 [rsc] --rw-rw-r-- M 173985 glenda sys 3439 Nov 13 07:20 sys/man/1/tar
	/n/sourcesdump/2005/1113/plan9/sys/man/1/tar:102,110 - 
	/n/sourcesdump/2005/1114/plan9/sys/man/1/tar:102,109
	  .TP
	  .B v
	  (verbose)
	- Print the name of each file treated
	- preceded by the function letter.
	- With 
	+ Print the name of each file as it is processed.
	+ With
	  .BR t ,
	  give more details about the
	  archive entries.
 [rsc] --rw-rw-r-- M 173985 glenda sys 21876 Nov 13 07:20 sys/src/cmd/tar.c
	/n/sourcesdump/2005/1113/plan9/sys/src/cmd/tar.c:248,256 - 
	/n/sourcesdump/2005/1114/plan9/sys/src/cmd/tar.c:248,256
	  
	  	if (first)
	  		seekable = seek(ar, 0, 1) >= 0;
	+ 	blkoff = seek(ar, 0, 1);		/* note position for `tar r' */
	  	/* try to size non-pipe input at first read */
	  	if (first && usefile) {
	- 		blkoff = seek(ar, 0, 1);	/* note position */
	  		n = read(ar, bufs, bytes);
	  		if (n <= 0)
	  			sysfatal("error reading archive: %r");