Fix wrong usage info message for cmd dumpuser, patch by Zack Middleton (#5024)

code/server/sv_ccmds.c

@@ -1220,7 +1220,7 @@ static void SV_DumpUser_f( void ) {
 	}
 
 	if ( Cmd_Argc() != 2 ) {
-		Com_Printf ("Usage: info <userid>\n");
+		Com_Printf ("Usage: dumpuser <userid>\n");
 		return;
 	}