fix: prevent infinite loop in enumerate_wildcard_locations

[egormkn]

This pull request fixes two issues in enumerate_wildcard_locations function:

1. When a wildcard domain passed to the function, it never returns. Even though wildcard domains are not supported at the moment, I think, infinite loop should be fixed. Currently any wildcard domain in any container configuration completely hangs the service.
2. In descending_wildcard_locations the first occurrence of last_label was removed, which might generate wrong wildcards:

#!/bin/bash

source ./functions.sh
enumerate_wildcard_locations test.com.example.com

# Output:
# *.com.example.com
# *.example.com
# test.example.com.*  <-- should be test.com.example.*
# test.example.*      <-- should be test.com.*
# test.*

[buchdag]

@egormkn thanks for this fix 👍

Do you think it would be possible to update the tests so that the bug you're fixing is covered ? I don't have permission to push to your fork.

[buchdag]

--- a/test/tests/location_config/expected-std-out.txt
+++ b/test/tests/location_config/expected-std-out.txt
@@ -1,7 +1,9 @@
-*.bar.baz.example.com
-*.baz.example.com
+*.bar.baz.com.example.com
+*.baz.com.example.com
+*.com.example.com
 *.example.com
-foo.bar.baz.example.*
+foo.bar.baz.com.example.*
+foo.bar.baz.com.*
 foo.bar.baz.*
 foo.bar.*
 foo.*

--- a/test/tests/location_config/run.sh
+++ b/test/tests/location_config/run.sh
@@ -54,7 +54,7 @@ function check_location {
}

# check the wildcard location enumeration function
-docker exec "$le_container_name" bash -c 'source /app/functions.sh; enumerate_wildcard_locations foo.bar.baz.example.com'
+docker exec "$le_container_name" bash -c 'source /app/functions.sh; enumerate_wildcard_locations foo.bar.baz.com.example.com'

# default configuration file should be empty
config_path="$vhost_path/default"