[Enhancement]Improve log message when image not available in cache

[apupier]

For Kit builder log, I have:

�[36mINFO�[0m[0030] Resolved base name fabric8/s2i-java:3.0-java8 to fabric8/s2i-java:3.0-java8 
�[36mINFO�[0m[0030] Resolved base name fabric8/s2i-java:3.0-java8 to fabric8/s2i-java:3.0-java8 
�[36mINFO�[0m[0030] Downloading base image fabric8/s2i-java:3.0-java8 
�[36mINFO�[0m[0031] Error while retrieving image from cache: getting file info: stat /kaniko/cache/sha256:9ac5acb3aa8e7e179eb1fd28cda7dac22ef7deac24f00b50cee56265fa259141: no such file or directory 
�[36mINFO�[0m[0031] Downloading base image fabric8/s2i-java:3.0-java8 
�[36mINFO�[0m[0032] Built cross stage deps: map[]                
�[36mINFO�[0m[0032] Downloading base image fabric8/s2i-java:3.0-java8 
�[36mINFO�[0m[0033] Error while retrieving image from cache: getting file info: stat /kaniko/cache/sha256:9ac5acb3aa8e7e179eb1fd28cda7dac22ef7deac24f00b50cee56265fa259141: no such file or directory 
�[36mINFO�[0m[0033] Downloading base image fabric8/s2i-java:3.0-java8 
�[36mINFO�[0m[0034] Executing 0 build triggers                   
�[36mINFO�[0m[0034] Skipping unpacking as no commands require it. 
�[36mINFO�[0m[0034] Taking snapshot of full filesystem...        
�[36mINFO�[0m[0034] Using files from context: [/builder/kit-bpb3eomt28oasvk8ae70/package/context] 
�[36mINFO�[0m[0034] ADD . /deployments                           
�[36mINFO�[0m[0034] Taking snapshot of files... 

when investigating, the message Error while retrieving image from cache: getting file info: stat /kaniko/cache/sha256:9ac5acb3aa8e7e179eb1fd28cda7dac22ef7deac24f00b50cee56265fa259141: no such file or directory leads to think that there is a a real error. Unless, I miss something, I think that it is only that the file is not available in the cache yet. I think it would be better to turn the message in this sense to avoid users to focus on this an "error" during investigations.

Also, I note that the message appears several times which seems a bit weird.

[astefanutti]

In upcoming RC2, the builder defaults to using Buildah instead of Kaniko, so the messages won't appear. These statements are emitted by Kaniko, so there isn't much that can be done on Camel K side.