Don't complain about unknown option if param is wrong

When a compound option was given an erroneous parameter,
for example "OPTIONS=runmode:foo",
you first got "Unknown runmode parameter 'foo", and
then "Unknown option 'runmode:foo'".

Prevent the Unknown option complaint, if we actually did
find a match.

src/options.c

@@ -472,6 +472,8 @@ parseoptions(register char *opts,boolean tinitial, boolean tfrom_file)
 
     if (optresult == optn_silenterr)
         return FALSE;
+    if (got_match && optresult == optn_err)
+        return FALSE;
     if (optresult == optn_ok)
         return retval;