db-connected resources created for tables that have an underscore in the name are not being fully created

Creating a REST Service with a db adapter named with underscores results in no service listed. Below an example with an API called "FirstAPI" and the following db-adapter (in the databse a table "api_user" exists):

global.php:
```php
<?php
return array(
    'db' => array(
        'adapters' => array(
            'db_mysql_apigility' => array(),
        ),
    ),
);
```

local.php:
```php
<?php
return array(
    'db' => array(
        'adapters' => array(
            'db_mysql_apigility' => array(
                'driver' => 'Pdo_Mysql',
                'database' => 'apigility',
                'username' => 'apigility',
                'password' => 'local',
                'hostname' => '127.0.0.1',
                'port' => '3306',
            ),
        ),
    ),
);
```


the command "ll -R module/FirstAPI/" results:

```
module/FirstAPI/:
total 24
drwxr-xr-x 5 florian florian 4096 Dez 13 16:33 ./
drwxr-xr-x 5 florian florian 4096 Dez 13 16:57 ../
drwxr-xr-x 2 florian florian 4096 Dez 13 16:33 config/
-rw-r--r-- 1 florian florian   51 Dez 13 16:33 Module.php
drwxr-xr-x 3 florian florian 4096 Dez 13 16:33 src/
drwxr-xr-x 2 florian florian 4096 Dez 13 16:33 view/

module/FirstAPI/config:
total 12
drwxr-xr-x 2 florian florian 4096 Dez 13 16:33 ./
drwxr-xr-x 5 florian florian 4096 Dez 13 16:33 ../
-rw-r--r-- 1 florian florian 3186 Dez 13 16:50 module.config.php

module/FirstAPI/src:
total 12
drwxr-xr-x 3 florian florian 4096 Dez 13 16:33 ./
drwxr-xr-x 5 florian florian 4096 Dez 13 16:33 ../
drwxr-xr-x 3 florian florian 4096 Dez 13 16:33 FirstAPI/

module/FirstAPI/src/FirstAPI:
total 16
drwxr-xr-x 3 florian florian 4096 Dez 13 16:33 ./
drwxr-xr-x 3 florian florian 4096 Dez 13 16:33 ../
-rw-r--r-- 1 florian florian  499 Dez 13 16:33 Module.php
drwxr-xr-x 4 florian florian 4096 Dez 13 16:33 V1/

module/FirstAPI/src/FirstAPI/V1:
total 16
drwxr-xr-x 4 florian florian 4096 Dez 13 16:33 ./
drwxr-xr-x 3 florian florian 4096 Dez 13 16:33 ../
drwxr-xr-x 3 florian florian 4096 Dez 13 16:50 Rest/
drwxr-xr-x 2 florian florian 4096 Dez 13 16:33 Rpc/

module/FirstAPI/src/FirstAPI/V1/Rest:
total 12
drwxr-xr-x 3 florian florian 4096 Dez 13 16:50 ./
drwxr-xr-x 4 florian florian 4096 Dez 13 16:33 ../
drwxr-xr-x 2 florian florian 4096 Dez 13 16:50 Api_user/

module/FirstAPI/src/FirstAPI/V1/Rest/Api_user:
total 16
drwxr-xr-x 2 florian florian 4096 Dez 13 16:50 ./
drwxr-xr-x 3 florian florian 4096 Dez 13 16:50 ../
-rw-r--r-- 1 florian florian  122 Dez 13 16:50 Api_userCollection.php
-rw-r--r-- 1 florian florian  107 Dez 13 16:50 Api_userEntity.php

module/FirstAPI/src/FirstAPI/V1/Rpc:
total 8
drwxr-xr-x 2 florian florian 4096 Dez 13 16:33 ./
drwxr-xr-x 4 florian florian 4096 Dez 13 16:33 ../

module/FirstAPI/view:
total 8
drwxr-xr-x 2 florian florian 4096 Dez 13 16:33 ./
drwxr-xr-x 5 florian florian 4096 Dez 13 16:33 ../
```



The command "cat module/FirstAPI/config/module.config.php" gives me:
```php
<?php
return array(
    'zf-mvc-auth' => array(
        'authorization' => array(),
    ),
    'router' => array(
        'routes' => array(
            'first-api.rest.api_user' => array(
                'type' => 'Segment',
                'options' => array(
                    'route' => '/api_user[/:api_user_id]',
                    'defaults' => array(
                        'controller' => 'FirstAPI\\V1\\Rest\\Api_user\\Controller',
                    ),
                ),
            ),
        ),
    ),
    'zf-versioning' => array(
        'uri' => array(
            0 => 'first-api.rest.api_user',
        ),
    ),
    'zf-rest' => array(
        'FirstAPI\\V1\\Rest\\Api_user\\Controller' => array(
            'listener' => 'FirstAPI\\V1\\Rest\\Api_user\\Api_userResource',
            'route_name' => 'first-api.rest.api_user',
            'identifier_name' => 'api_user_id',
            'collection_name' => 'api_user',
            'resource_http_methods' => array(
                0 => 'GET',
                1 => 'PATCH',
                2 => 'PUT',
                3 => 'DELETE',
            ),
            'collection_http_methods' => array(
                0 => 'GET',
                1 => 'POST',
            ),
            'collection_query_whitelist' => array(),
            'page_size' => 25,
            'page_size_param' => null,
            'entity_class' => 'FirstAPI\\V1\\Rest\\Api_user\\Api_userEntity',
            'collection_class' => 'FirstAPI\\V1\\Rest\\Api_user\\Api_userCollection',
        ),
    ),
    'zf-content-negotiation' => array(
        'controllers' => array(
            'FirstAPI\\V1\\Rest\\Api_user\\Controller' => 'HalJson',
        ),
        'accept_whitelist' => array(
            'FirstAPI\\V1\\Rest\\Api_user\\Controller' => array(
                0 => 'application/vnd.first-api.v1+json',
                1 => 'application/hal+json',
                2 => 'application/json',
            ),
        ),
        'content_type_whitelist' => array(
            'FirstAPI\\V1\\Rest\\Api_user\\Controller' => array(
                0 => 'application/vnd.first-api.v1+json',
                1 => 'application/json',
            ),
        ),
    ),
    'zf-hal' => array(
        'metadata_map' => array(
            'FirstAPI\\V1\\Rest\\Api_user\\Api_userEntity' => array(
                'identifier_name' => 'api_user_id',
                'route_name' => 'first-api.rest.api_user',
                'hydrator' => 'ArraySerializable',
            ),
            'FirstAPI\\V1\\Rest\\Api_user\\Api_userCollection' => array(
                'identifier_name' => 'api_user_id',
                'route_name' => 'first-api.rest.api_user',
                'is_collection' => true,
            ),
        ),
    ),
    'zf-apigility' => array(
        'db-connected' => array(
            'FirstAPI\\V1\\Rest\\Api_user\\Api_userResource' => array(
                'adapter_name' => 'db_mysql_apigility',
                'table_name' => 'api_user',
                'hydrator_name' => 'ArraySerializable',
                'controller_service_name' => 'FirstAPI\\V1\\Rest\\Api_user\\Controller',
            ),
        ),
    ),
);
```