MT#12347 Fix test api-rest/api-faxes.t: do not fail if fax is disabled

Otherwise we are failing with error:
> t/api-rest/api-faxes.t ..
> ok 1 - check faxserver feature state: disabled
> ok 2 - check error message in body: Faxserver feature is not active
> # Tests were run but no plan was declared and done_testing() was not seen.
> Dubious, test returned 254 (wstat 65024, 0xfe00)
> All 2 subtests passed
>
> Test Summary Report
> -------------------
> t/api-rest/api-faxes.t (Wstat: 65024 Tests: 2 Failed: 0)
>   Non-zero exit status: 254
>   Parse errors: No plan found in TAP output

Change-Id: Iff32b25ced931931af8cbaedc7fb054e48773667

t/api-rest/api-faxes.t

@@ -46,6 +46,7 @@ my $test_machine = Test::Collection->new(
         #if feature is inactive on the application level - there is nothing to test more
         #so added this pseudo test just to place it here. Really don't like it.
             ok($content->{message} =~ /$inactive_feature_msg/, "check error message in body: $inactive_feature_msg");
+            done_testing;
             exit();
         }
     }