Fix bug on missing hosts for SunRPC Portmap

Also cleans up and normalizes the print messages to follow the
conventions of "host:port - proto - message"

[FixRM #8409], reported by Chris F.

## Verification

 - [x] Run `auxiliary/scanner/misc/sunrpc_portmapper` against a host that's not listening on UDP/111.
 - [x] See the lack of a raise, as below.
 - [x] See the more beautiful status messages, as below.

Post-fix screen:

````
msf auxiliary(sunrpc_portmapper) > set rhosts www.metasploit.com
rhosts => www.metasploit.com
msf auxiliary(sunrpc_portmapper) > set verbose true
verbose => true
msf auxiliary(sunrpc_portmapper) > run

[*] 208.118.237.137:111 - SunRPC - Enumerating programs
[-] 208.118.237.137:111 - SunRPC - No response to Portmap request
[-] 208.118.237.137:111 - SunRPC - No response to SunRPC call for procedure: 4
[*] Scanned 1 of 1 hosts (100% complete)
[*] Auxiliary module execution completed
msf auxiliary(sunrpc_portmapper) > exit
````