replica/pull: fix usage
 [rsc] --rwxrwxr-x M 1138436 glenda sys 1465 Feb 16 09:20 rc/bin/replica/pull
	/n/sourcesdump/2006/0216/plan9/rc/bin/replica/pull:3,9 - 
	/n/sourcesdump/2006/0217/plan9/rc/bin/replica/pull:3,9
	  rfork en
	  
	  fn usage {
	- 	echo 'usage: replica/pull [-csnv] replica-name [paths]' >[1=2]
	+ 	echo 'usage: replica/pull [-nv] [-c name] [-s name] replica-name [paths]' >[1=2]
	  	exit usage
	  }