ChefAdapterImpl Junits
-Added new Unit tests for ChefAdapterImpl#trigger method
-Refactored ChefAdapterFactory to allow mock injection
-Added new create() method to ChefApiClientFactory which does not set
any Chef specific headers for the purpose of trigger method
-Cleaned up the trigger method - simplified usage, removed useless doFailure
method and inlined its logic and unified HttClient usage -> HttpClient is not
used directly but through existing ChefApiClient
-removed redundant TestChefAdapterImpl tests which have already been rewritten
Change-Id: I830d203877224aa2c5e1b0dff39d1171f1f2f0ef
Issue-ID: APPC-437
Signed-off-by: Michal Kabaj <michal.kabaj@nokia.com>