HisAppraiser: Set Result to UN_TRUSTED in case of not found analysis

This patch updates the behaviour of function doAnalyses()::
 - The result of the attestation request is set to UN_TRUSTED if
   one of the requested analysis does not exist.
 - The if..continue approach is replaced by an if..else approach,
   increasing the readability of the code.
 - It has been removed the verbose message from the status
   message "ANALYSIS_NOT_FOUND".

The patch is intended to be merged with the commit that defines
doAnalyses() (4df4e374be2668c73e61edd242bba7fd41a77783).