Issue #3421809 by mstrelan, Spokje: Remove unused variables in catch statements

core/includes/errors.inc

core/includes/form.inc

core/includes/install.core.inc

core/includes/theme.inc

core/includes/theme.maintenance.inc

core/includes/update.inc

...al/Component/PhpStorage/MTimeProtectedFastFileStorage.php

core/lib/Drupal/Component/Plugin/PluginManagerBase.php

core/lib/Drupal/Core/Access/AccessManager.php

core/lib/Drupal/Core/Access/CustomAccessCheck.php

core/lib/Drupal/Core/Asset/AssetDumper.php

core/lib/Drupal/Core/Batch/BatchStorage.php

core/lib/Drupal/Core/Cache/ChainedFastBackend.php

core/lib/Drupal/Core/Cache/Context/CacheContextsManager.php

core/lib/Drupal/Core/Cache/DatabaseBackend.php

core/lib/Drupal/Core/Cache/DatabaseCacheTagsChecksum.php

core/lib/Drupal/Core/Command/DbImportCommand.php

core/lib/Drupal/Core/Command/InstallCommand.php

core/lib/Drupal/Core/Command/ServerCommand.php

...ib/Drupal/Core/Condition/ConditionAccessResolverTrait.php