Bugfix: Setting and getting configuration values

- removed cache from global getter, because it was overriding the cache of
  the tenant specific getter
- changed Type of AuthName key, type of key was not important before the huge
  configuration refactoring
- fixed test conditions

Signed-off-by: Nonnenmacher Fabian <fabian.nonnenmacher@bosch-si.com>

hawkbit-repository/src/test/java/org/eclipse/hawkbit/repository/TenantConfigurationManagementTest.java

@@ -14,7 +14,6 @@ import org.eclipse.hawkbit.tenancy.configuration.TenantConfigurationKey;
 import org.eclipse.hawkbit.tenancy.configuration.validator.TenantConfigurationValidatorException;
 import org.junit.Assert;
 import org.junit.Test;
-import org.springframework.core.convert.ConversionFailedException;
 
 import ru.yandex.qatools.allure.annotations.Description;
 import ru.yandex.qatools.allure.annotations.Features;
@@ -86,7 +85,7 @@ public class TenantConfigurationManagementTest extends AbstractIntegrationTestWi
                 .isEqualTo(value2);
     }
 
-    @Test(expected = ConversionFailedException.class)
+    @Test(expected = TenantConfigurationValidatorException.class)
     @Description("Tests that the get configuration throws exception in case the value cannot be automatically converted from String to Boolean")
     public void wrongTenantConfigurationValueTypeThrowsException() {
         final TenantConfigurationKey configKey = TenantConfigurationKey.AUTHENTICATION_MODE_HEADER_ENABLED;