Allow rpcinfo.nse to set version info

The rpcinfo script can now set version info just like rpc-grind. Since
this requires considerably less traffic than rpc-grind, I made rpc-grind
depend on rpcinfo so that it will avoid running if we can get the
version information this way instead.

Also changed rpcinfo to only run on port 111, not on "rpcbind" service
since that's what -sV labels any detected RPC service.

scripts/rpc-grind.nse

@@ -30,8 +30,8 @@ Any other accept state is an incorrect behaviour.
 -- <target>
 --
 --@output
---PORT      STATE SERVICE          VERSION
---53344/udp open  walld (walld V1) 1 (RPC #100008)
+--PORT      STATE SERVICE VERSION
+--53344/udp open  walld   1 (RPC #100008)
 --
 
 
@@ -41,6 +41,8 @@ license = "Same as Nmap--See https://nmap.org/book/man-legal.html"
 
 categories = {"version"}
 
+-- Depend on rpcinfo so we don't grind something that's already known.
+dependencies = {"rpcinfo"}
 
 portrule = function(host, port)
   -- Do not run for excluded ports