Missing local meta data directory leads to a lot of exceptions

[MichaelRoeder]

Description

The controller constantly throws an exception when it tries to update the meta data of benchmarks and systems.

core_platform-controller.1.p6drvkjwv1sq@hobbitmaster.aksw.uni-leipzig.de    | java.lang.IllegalArgumentException: Parameter 'directory' is not a directory: metadata                                                              
core_platform-controller.1.p6drvkjwv1sq@hobbitmaster.aksw.uni-leipzig.de    |   at org.apache.commons.io.FileUtils.validateListFilesParameters(FileUtils.java:2629)                                                               
core_platform-controller.1.p6drvkjwv1sq@hobbitmaster.aksw.uni-leipzig.de    |   at org.apache.commons.io.FileUtils.innerListFilesOrDirectories(FileUtils.java:1543)                                                               
core_platform-controller.1.p6drvkjwv1sq@hobbitmaster.aksw.uni-leipzig.de    |   at org.hobbit.controller.docker.FileBasedImageManager$1.run(FileBasedImageManager.java:70)                                                        
core_platform-controller.1.p6drvkjwv1sq@hobbitmaster.aksw.uni-leipzig.de    |   at java.base/java.util.TimerThread.mainLoop(Timer.java:556)

Reproducability

Deploy the platform locally.

Expected behavior

It shouldn't throw any exception. It is fine to state once that the directory is not available and, hence, no local meta data will be loaded.

[denkv]

A similar situation arises when GitLab is not reachable.